Topographic Maps
Lesson Objectives
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Define a topographic map and state
its uses.
Describe how contour lines show the
elevations, shape, and slope of the
land.
Compare a satellite photo to a
topographic map.
What is a topographic map?
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A topographic map, also known as a
contour map, is a map that shows
the shape of the land using contour
lines.
It is a map that shows an elevation
field, meaning how high and low the
ground is in relation to sea level.
What are contour lines?
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Contour lines are lines that connect
points that are of the same
elevation.
They show the exact elevation, the
shape of the land, and the steepness
of the land’s slope.
Considering this, could they ever
touch or cross?
Contour Intervals
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A contour interval is the difference in
elevation between two contour lines
that are side by side.
Remember that a contour interval is
NOT the distance between the two
lines – to get the distance you need
to use the map scale.
Index Contours
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Index contours – contour lines that
are labeled to help you find the
contour interval.
What if my contour lines are close
together?
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If the contour lines are close
together, then that indicates that
area has a steep slope
What if my contour lines are far
apart?
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If the contour lines are far apart,
then that indicates the land has a
gentle slope (low slope).
What do depressions in the map
look like?
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A depression, such as the inside of a
dead volcano, is represented by
Hachure lines, regular contour lines
with small segments sticking out
from it.
The first hachure line is at the same
elevation as the contour line before
it.
More on Contour Lines
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Contour lines form
V’s that point
upstream when
they cross a
stream.
It is important to
remember that
they point in the
opposite direction
as the flow of
water.
Now that I know what a topographic
map is, how do I read it?
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First determine the contour interval (the
distance between each contour line)
Then determine the map scale (usually at
the bottom of the map)
Identify any hills or depressions
0 ft is equal to water level, because
elevation is based on how much higher a
point is then the water nearby
Reading a topographic map cont.
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Look for areas where the contour
lines are close together – they
indicate a steep area.
Look for areas where the contour
lines are spread apart – they indicate
a gentle slope.
Shows 3D in a 2D way from a birds eye
view
http://raider.muc.edu/~mcnaugma/Topographic%20Maps/contour.h
2. What about
areas between
the contours?
1. What is the
elevation for
each letter?
http://raider.muc.edu/~mcnaugma/Topographic%20Maps/contour.h
Topographic
Maps
Map Reading Activity: Topography
1. Approximately how tall is Able Hill?
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3. Approximately how tall is Baker Hill?
_______________________
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4. Which mountain is taller, and by about
how much?
_______________________
____
5. How many meters of elevation are
there between contour lines on the
topographic map?
_______________________
____
6. Which mountain has steeper slopes?
_______________________
____
7. Are the contour lines closer together
on Able Hill or Baker Hill?
_______________________
____
Answers
1. Elevations on the topographic map
are in color as follows: Red-over 50m,
Orange-from 40-50m, Yellow-from 3040m, Light green-from 20-30m, Dark
green-from 10-20m, Purple-from 010m.
2. Approximately how tall is Able Hill?
about 42m
3. Approximately how tall is Baker Hill?
about 51m
4. Which mountain is taller, and by
about how much?
Baker Hill by about 9m
5. How many meters of elevation are
there between contour lines on the
topographic map? 10 m
6. Which mountain is steeper?
Baker Hill
7. Are the contour lines closer
together on Able Hill or Baker Hill?
Baker Hill
Topographic Maps
1. Color the elevations on the topographic
map as follows. Red: 50m and higher,
Orange: 40-50m, Yellow: 30-40m, Light
green: 20-30m, Dark green: 10-20m, Purple:
0-10m.
2. Finish the mountain diagram below the
topographic map, completing Oak Hill and
drawing Ash Hill with proper elevations.
3. Approximately how tall is Ash Hill?
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4. Approximately how tall is Oak Hill?
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5. Which mountain is taller?
_________________________
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6. How many meters of elevation are there
between contour lines on the topographic
map?
_________________________
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7. Are the contour lines closer together on
Ash Hill or Oak Hill?
_________________________
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8. Which mountain has steeper slopes?
_________________________
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Answers
1. The elevations on the topographic
map are as follows: Red-over 50m,
Orange-from 40-50m, Yellow-from 3040m, Light green-from 20-30m, Dark
green-from 10-20m, Purple-from 010m.
2. Oak Hill and Ash Hill are completed
with proper elevations as shown.
3. Approximately how tall is Ash Hill?
About 51-52m
4. Approximately how tall is Oak Hill?
About 41-45m
5. Which mountain is taller? Ash Hill
6. How many meters of elevation are
there between contour lines on the
topographic map? 10m
7. Are the contour lines closer
together on Ash Hill or Oak Hill?
Ash Hill
8. Which mountain has steeper
slopes?
Ash Hill
Review Questions
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How are contour lines drawn on
maps?
How does a contour map show
whether a slope is gentle or steep?
How is distance measured on a
contour map?