Transcript Topographic Maps - Sonoma Valley High School

Topographic maps
Topographic Map: Represents
Earth’s 3-dimensional surface in
two dimensions
3 – D surface
2 – D surface
Topographic Map
Topographic maps use contour lines to
show elevation or height above sea level
Can you see
the
relationship?
Topographic
Map
Symbols
White board: draw
the symbols for
railroad tracks.
Topo Map Scales
A scale is the comparison of the
distance on the map to the
actual distance covered.
1.0
½
0
A Map Scale can
be graphic
Map Scale
1.0
Fractional Map Scale
Found in bottom margin of a topo map.
Scale will look something like this
1:24,000
This means one unit of map measurement is
equal to 24,000 units of land measurement.
Example: One cm on the map is equal to
24,000 cm on the ground.
Same as saying the map is 1/24,000 the size of
the area it represents.
Contour Lines
A line connecting points of the same
elevation.
14000 ft at
this contour
line
Contour Line Rules
Contour lines do not cross
or intersect each other
Contour lines are widely
spaced on gentle slopes or
flatter land.
Contour lines are closely
spaced on steep slopes.
Evenly spaced contour lines
indicate a uniform slope.
Index Contour Lines
Lines with elevation number on them
Index Contour Line
Pair share: How
many feet does the
index line
represent?
Contour Intervals
The difference (in feet or meters) from one
contour line to the next
How to find the contour interval:
High Index Line Number – Low Index number
Number of Spaces in Between
Contour Interval = 200 – 100
5
Contour Interval = 20 feet
White board review
1. What to Topo maps
represent that other maps
don’t?
2. What do contour line show?
3. What are contour intervals?
4. Which box is over a steeper
are A or B?
A
B