Slide 1

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 2

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 3

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 4

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 5

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 6

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 7

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 8

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 9

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 10

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 11

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 12

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 13

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 14

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 15

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 16

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 17

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 18

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 19

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 20

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 21

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 22

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 23

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 24

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 25

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 26

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 27

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 28

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 29

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 30

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 31

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 32

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 33

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 34

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 35

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 36

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 37

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 38

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 39

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 40

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 41

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 42

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 43

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 44

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 45

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 46

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 47

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 48

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 49

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 50

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 51

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 52

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 53

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 54

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 55

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 56

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 57

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 58

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 59

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 60

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 61

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 62

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 63

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 64

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 65

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 66

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 67

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 68

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 69

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 70

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 71

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 72

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 73

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 74

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 75

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 76

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 77

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 78

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 79

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 80

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 81

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 82

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 83

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 84

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 85

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 86

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 87

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 88

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 89

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 90

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 91

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 92

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 93

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 94

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 95

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 96

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 97

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.


Slide 98

How to Use This Presentation
• To View the presentation as a slideshow with effects
select “View” on the menu bar and click on “Slide Show.”
• To advance through the presentation, click the right-arrow
key or the space bar.
• From the resources slide, click on any resource to see a
presentation for that resource.
• From the Chapter menu screen click on any lesson to go
directly to that lesson’s presentation.
• You may exit the slide show at any time by pressing
the Esc key.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Resources

Chapter Presentation

Transparencies

Visual Concepts

Standardized Test Prep

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Table of Contents
Section 1 Finding Locations on Earth
Section 2 Mapping Earth’s Surface

Section 3 Types of Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Objectives
• Distinguish between latitude and longitude.
• Explain how latitude and longitude can be used to
locate places on Earth’s surface.
• Explain how a magnetic compass can be used to
find directions on Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude
• The points at which Earth’s axis of rotation intersects
Earth’s surface are used as reference points for
defining direction. These points are the geographic
North Pole and South Pole.
• Halfway between the poles, a circle called the
equator divides Earth into the North and Southern
Hemispheres.
• A reference grid that is made up of additional circles
is used to locate places on Earth‘s surface.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
• One set of circles describes positions north and south
of the equator. These circles are known as parallels,
and they express latitude.
• parallel any circle that runs east and west around
Earth and tat is parallel to the equator; a line of
latitude
• latitude the angular distance north or south from the
equator; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
The diagram below shows Earth’s parallels.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Latitude, continued
Degrees of Latitude
• Latitude is measured in degrees, and the equator is 0° latitude.
The latitude of both the North Pole and the South Pole is 90°.
• In actual distance, 1° latitude equals about 111 km.

Minutes and Seconds
• Each degree of latitude consists of 60 equal parts, called
minutes. One minute (symbol: °) of latitude equals 1.85 km.
• In turn, each minute is divided into 60 equal parts, called
seconds (symbol: °).
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
• East-west locations are established by using
meridians.
• meridian any semicircle that runs north and south
around Earth from the geographic North Pole to the
geographic South Pole; a line of longitude
• longitude the angular distance east or west from the
prime meridian; expressed in degrees

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
The diagram below shows Earth’s meridians.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Longitude, continued
Degrees of Longitude
• The meridian that passes through Greenwich, England is called
the prime meridian. This meridian represents 0° longitude.
• The meridian opposite the prime meridian, halfway around the
world, is labeled 180°, and is called the International Date Line.

Distance Between Meridians
• The distance covered by a degree of longitude depends on
where the degree is measured. The distance measured by a
degree of longitude decreases as you move from the equator
toward the poles.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Comparing Latitude and Longitude

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles
• A great circle is any circle that divides the globe into halves, or
marks the circumference of the globe.
• Any circle formed by two meridians of longitude that are directly
across the globe from each other is a great circle.
• The equator is the only line of latitude that is a great circle.
• The route along a great circle is the shortest distance between
two points on a sphere. As a result, great circles are commonly
used in navigation, such as for air and sea routes.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
The diagram below shows what a great circle is.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Great Circles, continued
Reading Check
Why is the equator the only parallel that is a great
circle?

because the equator is the only parallel that divides
Earth into halves

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction
• One way to find direction on Earth is to use a magnetic
compass.
• A magnetic compass can indicate direction because Earth has
magnetic properties as if a powerful bar-shaped magnet were
buried at Earth’s center at an angle to Earth’s axis of rotation.
• The areas on Earth’s surface just above where the poles of the
imaginary magnet would be are called the geomagnetic poles.

• The geomagnetic poles and the geographic poles are located in
different places.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
Magnetic Declination
• The angle between the direction of the geographic pole and the
direction in which the compass needle points is called magnetic
declination.

• In the Northern Hemisphere, magnetic declination is measured
in degrees east or west of the geographic North Pole.
• Because Earth’s magnetic field is constantly changing, the
magnetic declinations of locations around the globe also change
constantly.
• By using magnetic declination, a person can use a compass to
determine geographic north for any place on Earth.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The diagram below shows the magnetic declination of the United
States.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 1 Finding Locations on
Earth

Finding Direction, continued
The Global Positioning System
• Another way people can find their location on Earth is by using
the global positioning system, or GPS.

• GPS is a satellite navigation system that is based on a global
network of 24 satellites that transmit radio signals to Earth’s
surface.
• A GPS receiver held by a person on the ground receives signals
from three satellites to calculate the latitude, longitude, and
altitude of the receiver on Earth.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Objectives
• Explain two ways that scientists get data to make
maps.
• Describe the characteristics and uses of three types
of map projections.
• Summarize how to use keys, legends, and scales to
read maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

How Scientists Make Maps
• Because most globes are too small to show details of Earth’s
surface, such as streams and highways, a great variety of maps
have been developed for studying and displaying detailed
information about Earth.
• The science of making maps is called cartography. Scientists
who make maps are called cartographers.
• Cartographers use data from a variety of sources, such as from
field surveys and remote sensing.
• remote sensing the process of gathering and analyzing
information about an object without physically being in touch
with the object
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections
• A map is a flat representation of Earth’s curved surface.
• Transferring a curved surface to a flat map results in a distorted
image of the curved surface. An area shown on a map may be
distorted in size, shape, distance, or direction.

• Over the years, cartographers have developed several ways to
transfer the curved surface of Earth onto flat maps. These
methods are called map projections.
• map projection a flat map that represents a spherical surface

• No map projection is entirely accurate, but each kind of
projection has advantages and disadvantages.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Cylindrical Projections
• If you wrapped a cylinder of paper around a lighted globe and
traced the outlines of continents, oceans, parallels, and
meridians, a cylindrical projection would result.

• A cylindrical projection is accurate near the equator but distorts
distances and sizes near the poles.
• One advantage to cylindrical projections is that parallels and
meridians form a grid, which makes locating positions easier.

• On a cylindrical projection, shapes of small areas are usually
well preserved.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a cylindrical projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Reading Check
Why do meridians and parallels appear as a grid when
shown on a cylindrical projection?

Because both the parallels and the meridians are
equally spaced straight lines on a cylindrical
projection, the parallels and meridians form a grid.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Azimuthal Projections
• A projection made by placing a sheet of paper against a globe
such that the paper touches the globe at only one point is called
an azimuthal projection.
• On an azimuthal projection, little distortion occurs at a the point
of contact, but the unequal spacing between parallels causes a
distortion in both direction and distance that increases as
distance from the point of contact increases.

• One advantage of azimuthal projections is that on these maps,
great circles appear as straight lines. Thus, azimuthal
projections are useful for plotting navigational paths.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows an azimuthal projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
Conic Projections
• A projection made by placing a paper cone over a lighted globe
so that the axis of the cone aligns with the axis of the globe is
known as a conic projection.

• Areas near the parallel where the cone and the globe are in
contact are distorted least.
• A series of conic projections can be used to increase accuracy
by mapping a number of neighboring areas and fitting the
adjoining areas together to make a polyconic projection.

• On a polyconic projection, the relative sizes and shapes of small
areas on the map are nearly the same as those on the globe.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Map Projections, continued
The diagram below shows a conic projection.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map
• Maps provide information through the use of symbols.

Direction on a Map
• Maps are commonly drawn with north at the top, east at the
right, west at the left, and south at the bottom.
• Some maps use parallels of latitude and meridians of longitude
to indicate direction and location.
• Many maps also include a compass rose, which is a symbol that
indicates the cardinal directions (north, east, south, and west),
or an arrow that indicates north.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Symbols
• Symbols are commonly used on maps to represent features
such as cities, highways, rivers, and other points of interest.
• Symbols may resemble the features that they represent, or they
may be more abstract.
• Symbols are commonly explained in a legend.
• legend a list of map symbols and their meanings

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Information on Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Map Scales
• scale the relationship between the distance shown on a map
and the actual distance
• Map scales are commonly expressed as graphic scales,
fractional scales, or verbal scales.
• A graphic scale is a printed line that has markings that represent
units of measure, such as meters or kilometers.

• A fractional scale is a ratio that indicates how distance on Earth
relates to distance on the map.
• A verbal scale expresses scale in sentence form.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Reading Check
Name three ways to express scale on a map.
by using a graphic scale, or a printed line divided into
proportional parts that represent units of measure; a
fractional scale, in which a ratio shows how distance
on Earth relates to distance on a map; or a verbal
scale, which expresses scale in sentence form

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 2 Mapping Earth’s
Surface

Reading a Map, continued
Isograms
• isogram a line on a map that represents a constant or equal
value of a given quantity
• The second part of the word, -gram, can be changed to
describe the measurement being graphed. For example,
when the line connects points of equal temperature the line
is called an isotherm. When the line connects points of equal
atmospheric pressure, the line is called an isobar.

• Isograms can be used to plot many types of data, such as
atmospheric pressure, temperature, precipitation, gravity,
magnetism, density, elevation, chemical composition, and
many others.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Objectives
• Explain how elevation and topography are shown on
a map.
• Describe three types of information shown in
geologic maps.
• Identify two uses of soil maps.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps
• One of the most widely used maps is called a topographic map,
which shows the surface features of Earth.
• topography the size and shape of the land surface features of a
region
• elevation the height of an object above sea level

Advantages of Topographic Maps
• Topographic maps provide more detailed information about the
surface of Earth than either drawins or .

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Elevation on Topographic Maps
• On topographic maps, elevation is shown by using contour lines.
• contour line a line that connects points of equal elevation on a
map
• The difference in elevation between one contour line and the
next is called the contour interval. The contour interval is
selected based on the relief of the area being mapped.
• relief the difference between the highest and lowest elevations
in a given area
• Every fifth contour line is darker than the four lines one either
side of it. This index contour makes reading elevation easier.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps
• The spacing and direction of contour lines indicate the shapes of
the landforms represented on a topographic map.

• Closely spaced contour lines indicate that the slope is steep.
• Widely spaced contour lines indicate that the land is relatively
level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Landforms on Topographic Maps, continued
• A contour line that bends to form a V shape indicates a valley.
The bend in the V points toward the higher end of the valley; this
V points upstream, or in the direction from which the water
flows, if there is a stream.
• Contour lines that form closed loops indicate a hilltop or a
depression. Closed loops that have short straight lines
perpendicular to the inside of the loop indicate a depression.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
The diagram below shows how topographic maps represent
landforms.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps and Contour Lines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Reading Check
Why do V-shaped contour lines along a river point
upstream?

Water moves from areas of higher elevation to areas of
lower elevation. Because the V shape points toward
higher elevation, it points upstream.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Topographic Maps, continued
Topographic Map Symbols
• Symbols are used to show certain features on topographic
maps.
• Symbol color indicates the type of feature. Constructed features,
such as buildings, are shown in black. Highways are shown in
red. Bodies of water are colored blue, and forested areas are
colored green.
• Contour lines are brown or black.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Index Contour, Contour Interval, and Relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps
• Geologic maps are designed to show the distribution of geologic
features, such as the types of rocks found an a given area and
the locations of faults, folds, and other structures.

Rock Units on Geologic Maps
• On geologic maps, geologic units are distinguished by color.
Units of similar ages are generally assigned colors in the same
color family, such as different shades of blue.
• In addition to assigning a color, geologists assign a set of letters
to each rock unit. This set of letters symbolizes the age of the
rock and the name of the unit or the type of rock.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Geologic Maps, continued
Other Structures on Geologic Maps
• Other markings on geologic maps are contact lines. A contact
line indicates places at which two geologic units meet, called
contacts.
• The two main types of contacts are faults and depositional
contacts.
• Geologic maps also indicate the strike and slip of rock beds.
Strike indicates the direction in which the beds run, and dip
indicates the angle at which the beds tilt.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps
• Scientists construct soil maps to classify, map, and describe
soils, based on surveys of soils in a given area.

Soil Surveys
• A soil survey consists of three main parts: text, maps, and
tables.
• The text includes general information about the geology,
topography, and climate of the area.

• The tables describe the types and volumes of soils in the area.
• The maps show the approximate locations and types of the
different soils.
Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Reading Check
Why do scientists create soil maps?
Scientists create soil maps to classify, map, and
describe soils.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Soil Maps, continued
Uses of Soil Maps
• Soil maps are valuable tools for agriculture and land
management.

• Soil maps are used by farmers, agricultural engineers, and
government agencies.
• The information in soil maps and soil surveys helps developers
and agencies identify ways to conserve and use soil and plan
sites for future development.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Section 3 Types of Maps

Other Types of Maps
• Maps are useful to every branch of Earth science.
• Maps that show topography and rock and soil types
are only one useful type of map.
• Some Earth scientists use maps to show the location
and flow of both water and air.
• Other types of Earth scientists use maps to study
changes in Earth’s surface over time.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Maps in Action

Maps in Action
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Models of the Earth

Brain Food Video Quiz

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
1. How can you determine whether the contours on a
topographic map show a gradual slope?
A. Look for V-shaped contour lines.
B. Look for widely spaced contour lines.
C. Look for short, straight lines inside the loop.
D. Look for tightly spaced, circular contour lines.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
2. How far apart would two successive index contours
be on a map with a contour interval of 5 meters?
F.
G.
H.
I.

5 meters
10 meters
20 meters
25 meters

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
3. What part of a road map would you use in order to
measure the distance from your current location to
your destination?
A. latitude lines
B. map scale
C. longitude lines
D. map legend

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
4. Meteorologists use isobars on a weather map in
order to?
F.
G.
H.
I.

show changes in atmospheric air pressure.
connect points of equal temperature.
plot local precipitation data.
show elevation above or below sea level.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Multiple Choice, continued
5. What is the angular distance, measured in degrees,
east or west of the prime meridian?
A. latitude
B. longitude
C. isogram
D. relief

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response
6. At what location on Earth does each new day begin
at midnight?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
6. At what location on Earth does each new day begin
at midnight?
International Date Line

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Short Response, continued
7. What is the latitude of the North Pole?
90°N

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills
Read the passage below. Then, answer questions 9–11.

Map Projections
Earth is a sphere, and thus its surface is curved. When a curved surface is
transferred to a flat map, distortions in size, shape, distance, and direction occur. To
limit these distortions, cartographers have developed many ways of transferring a
three-dimensional curved surface to a flat map. On Mercator projections, meridians
and parallels appear as straight lines. These lines cross each other at 90° angles
and form a grid. On gnomonic projections, there is little distortion at one contact
point on the map, which is often one of the poles. But distortion in direction and
distance increases as distance from the point of contact increases. On conic
projections, the map is accurate along one parallel of latitude. Areas near this
parallel are distorted the least. However, none of these maps is an entirely accurate
representation of Earth’s surface.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
9. Which of the following appears as a straight line on
a gnomonic projection, where the point of contact is
the North Pole?
A. great circles
B. parallels
C. the equator
D. coastlines

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
10. Which of the following statements about Mercator projections is
true?
F.

Because latitude and longitude form a grid, plotting great
circles can be done by using a straight-edged ruler.
G. Because latitude and longitude form a grid, finding specific
locations is easy on a Mercator map projection.
H. Mercator maps often show the greatest distortion where
the projection touched the globe.
I. Mercator maps often show polar regions as being much
smaller than they actually are.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Reading Skills, continued
11. Why does each map described display some sort of
distortion?
Any time a curved surface is mapped on a flat
surface, distortion occurs. This distortion can take
different forms and each map type produces
different amounts of distortion.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics
Use the figure below to answer questions 12–13. The
figure shows the topography of the an area
surrounding the Orr River.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
12. What location on the map has the steepest
gradient?
A. location A
B. location B
C. location C
D. location D

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
13. In which direction is the river in the topographic map
flowing? What information on the map helped you
determine your answer?
Answers should include the following: The river is
flowing from northwest to southeast; the contour
lines near the river form V shapes, and the tips of
the Vs point upstream; the Vs in the map point to the
northwest.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
Use the figure below to answer questions 14–15.
The figure shows Earth’s system of latitude and
longitude lines. Lines are shown in 30° increments.

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
14. Which point is located at 30°N, 60°E?
F. point E
G. point F
H. point G
I. point H

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3

Standardized Test Prep

Interpreting Graphics, continued
15. The distance between two lines of latitude that are
1° apart is about 111 km. What is the approximate
distance between points G and E?
111 km/1°  60° = 6660 km

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Parallels

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Meridians

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Great Circles

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Magnetic Declination of the United States

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Map Projections

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Maps

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.

Chapter 3
Topographic Map of the Desolation Watershed

Chapter menu

Resources

Copyright © by Holt, Rinehart and Winston. All rights reserved.