Reading and Interpreting Topographic Maps

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Peaks and Valleys

• Reading and Interpreting Topographic Maps

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Peaks and Valleys
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Key Terms
Elevation
Topographic Map
Contour Line
Contour Interval
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Elevation

• A term that describes the height of a point on
  Earths surface above (or below) sea level.
• This point is 6300 feet (1920 meters) above sea
  level.

http//www.math.montana.edu/nmp/materials/ess/mou
ntain_environments/novice/yosemite.jpg
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Topographic Map

• A map that show the elevation of the land, such
  as hills and valleys, using contour lines.

http//www.math.montana.edu/nmp/materials/ess/mou
ntain_environments/novice/yosemite.jpg
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Contour Lines
http//www.topozone.com/map.asp?lat35.16670759393
963lon-106.71383553979156s25sizelsymshown
Contour lines are lines connecting points of
equal elevation. Every point along the line lies
at the same elevation above sea level. Imagine
walking around a hill in such a way that you
never go up or down the hill, but stay at the
same level. The trace of your path would be a
contour line of that elevation.
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Contour Interval

• The vertical distance between one contour line
  and the next. On any map, the contour interval
  must be constant, and must be shown in the maps
  legend. On this map, the contour interval is 20
  feet, because each line represents a 20 foot
  increase in elevation.

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Rules for Successful ContouringRule 1

• Every point along a contour line represents the
  same elevation.
• This entire line represents 1200 feet above sea
  level.

1200
1150
1250
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Rules for Successful ContouringRule 2

• Contour lines NEVER split or divide!
• Cant happen!

1150
1200
1150
1250
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Rules for Successful ContouringRule 3
This is fine!

• Contour lines cannot just stop. They must either
  form a closed loop, or run off the edge of your
  map.
• Whats the elevation here???

1100
1200
1150
1250
?
?
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Rules for Successful ContouringRule 4

• Contour lines NEVER, EVER cross
• Whats going on?? Is this area above or below
  1200 feet?

1100
1200
1150
1250
?
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Tip 1 What does contour line spacing indicate?

• The closer together the contour lines are, the
  steeper the hill is. The more spread apart they
  are, the gentler the slope.
• Traveling along the red line would be much
  steeper than traveling along the green line.

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Tip 2 Which way is the stream flowing?

• When contour lines cross a stream or river, they
  form v-shaped kinks in the lines that always
  point upstream.
• Also remember - Water always flows DOWNHILL!

Blue Creek flow towards the East.
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Tip 3 Finding the hill tops

• Hill tops are easy to find. Just look for the
  concentric closed contour lines that form the top
  of a hill. Notice the contour lines that form
  the two peaks below.

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Tip 4 What do those funny hachure marks mean?

• Some features, such as the Grand Canyon, lakes,
  mines, or sinkholes actually are holes in the
  ground. The hachured contours indicate a
  depression. Dont confuse it with a hilltop!

800
700
600
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TOPO QUIZNow its time to test your topography
map reading skills. Good Luck!!
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• If you traveled from point A to point B, would
  you be going uphill or downhill?
• What landform do you think this map depicts?
• a. Valley
• b. Mountain
• c. Plain

700
750
A
800
X
825
B
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Correct!
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Sorry

• Actually, you would be going uphill. Look at the
  elevations on the contour lines you will be
  crossing.

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Sorry
Please try again.
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• In which direction does Maple Creek flow?
• Northeast
• Southwest
• Cant tell from information given
• What is the contour interval of this map?
• 50
• 100
• 400

800
600
700
500
Maple Creek
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• 5. What is the approximate elevation at the top
  of this hill?
• a. 1240
• b. 1300
• c. 1000
• 6. Which hike would be steeper, from A to B or
  from C to D?

C
D
1200
B
1150
A
1100
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• 7. What is the contour interval of this map?
• a. 20 feet
• b. -20 feet
• c. 60 feet
• 8. What type of landform is depicted here?
• a. a mountain
• b. a depression
• c. a valley

60
40
20
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Link to Topozone

• The USGS publishes topographic maps of the entire
  country. This website allows you to view any of
  these topographic maps.
• Go to this site and use the map search to try to
  locate your city, town, school, or maybe even
  your own house. When you find a familiar area,
  examine the contours to see how well you
  recognize your own topographic features!