Transcript Document

Aim: How do we read Topographic
Maps?
Do Now:
In your notes, list all the different
types of landforms/features of
Earth that you can think of.
Example: Hills
Topography:
The shape of the
land.
Grand Canyon, Arizona
Napa Valley, California
K2, Pakistan
Topographic Maps:
• Represent the shape of the land on a
flat piece of paper.
• Isolines/Contour Lines represent
different elevations on a topographic
map.
• Each isoline connects values that
are equal.
“iso” means equal
m
m
m
m
m
Altitude:
The height above sea-level or above a specific
point on a map.
What value
is sea-level?
Get the Altitude worksheet from the back of
the room. You and your partner should work
on this worksheet together. We will go over it
in 10 min.
I. Parts of Topographic maps:
a) Index Contour Lines: labeled
with the
elevation.
Using the index contour
lines, determine the
value of the lines in
between.
Index contour lines
b) Contour Interval:
• Represents a vertical measurement
(up hill or down hill).
• Measurement that separates contour
lines.
c) Hachure marks:
Copy diagram
into notes
refer to a drop in elevation
(depression/hole in the ground).
- The first hachured line
repeats the same value
as the countour line
before it.
- The second hachured line
counts down by the
contour interval.
d) Bench mark: shows the exact
elevation at that point.
E) River and Streams
When a river or stream crosses a contour line,
the contour line bends and points upstream.
upstream
• Upstream is where the
river starts.
• Downstream is where
the river ends.
downstream
II. Calculations on Contour Maps
a) Gradient
• Refers to the steepness of the land (slope)
Closer contour lines = steep slopes.
N
Which side
of the hill is
the steepest?
WHY?
Further contour lines = gradual slopes.
b) The highest possible point
will always be one unit of measure less than
the next possible contour line.
What is the
highest
possible
value of X?
X
Contour Interval = 10 m
10 m
Closure
Obtain the worksheet called “Reading a
Topographic Map” from the back table
and complete the worksheet. We will go
over it when finished.