Topographic Maps

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Topographic Maps
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What is a Topographic Map?

• In contrast to most maps, a topographic map
  shows the shape of the Earths surface by using
  contour lines.

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• Topographic Map
• A map that shows the surface features of Earth
• Shows the elevation of a specific area
• Height of an object above sea level

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• Parts of a Topographic Map
• Contour Lines
• A line that connects points of equal elevation
• Used to show features of the land
• Mountains, valleys, etc

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• Contours are imaginary lines that join points of
  equal elevation above or below sea level.

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• Features of a Topographic Map
• Natural Features
• Rivers, lakes
• Mountains
• Artificial (man made) features
• Cities
• Roads, bridges

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• Contour Lines
• Spacing of lines depends on slope characteristics
• Close contour lines steeper slope
• Farther apart contour lines gentle slope

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• Contour Interval
• The difference in elevation between one contour
  line and the next
• Based on the areas relief
• The difference between the highest and lowest
  points in an area

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• Index Contour
• A darker, bolder contour line that indicates a
  change in elevation
• Usually found every fifth contour line

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• Reading Topographic Maps
• Features on Earths surface can be represented by
  colors
• Blue Water
• Brown contour lines
• Green wooded areas

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• Golden Rules of Topographic Maps
• Contour lines never cross, all points on a line
  represent one elevation
• Spacing of contour lines depends on steepness of
  slope
• Close steep slope
• Far apart gentle slope

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• Contour lines that cross a valley or stream are
  V-shaped
• The V points towards the area of highest
  elevation
• Tops of mountains or hills are shown by closed
  circles
• Depressions have hash marks pointing towards the
  center

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Lets take a walk up a hill!
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Were now at an elevation of 100 meters.
100m
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Lets keep going!
100m
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Now were at 200m.
200m
100m
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Shall we march on?
200m
100m
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Weve made it to 300m!
300m
200m
100m
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On to the peak!
300m
200m
100m
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Were on the peak, but whats our elevation?
300m
200m
100m
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Any ideas?
Lets add contour lines for every 50 meters and
see if that helps.
300m
200m
100m
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We know that we are above 350m, but less than
400m.
350m
300m
250m
200m
150m
100m
50m
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Lets head down the hill, its getting late!
350m
300m
250m
200m
150m
100m
50m
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Now whats our elevation?
If you said somewhere between 200m and 250m you
are right!
350m
300m
250m
200m
150m
100m
50m
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Lets try this again!
350m
300m
250m
200m
150m
100m
50m
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Whats our elevation now?
If you said 50m or just under, youre right!
350m
300m
250m
200m
150m
100m
50m
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Lets now look at the same hill, but the way we
might see it from an airplane!
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Each color change represents a 50 meter increase.
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Now, lets try the same hike! Our elevation is 0
meters.
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Now what is our elevation?
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If you said more than 150 meters, but less than
200 meters your right!
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Lets go a little higher.
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Think you know our elevation now?
More than 300meters But less than 350meters
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If we were standing on the peak, what would be
our elevation?

• More than 350 meters, less than 400 meters

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Lets head down hill.
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Know our elevation?
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More than 100 meters, less than 150 meters
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Lets see what you know.
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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Quiz Time

• Grab a piece of paper and write your answers to
  the following questions.
• Ready?

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1. Could the elevation at the peak (B) be 1410
meters?
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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2. What is the elevation at (E)?
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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3.What is the elevation difference between (A)
and (B)?
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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4. Could the elevation at (F) be 417 meters?
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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5. If you walked a straight line from (D) to (C)
would you walk over a ridge or down a valley?
E
C
D
B
1200m
F
1000m
A
800m
400m
600m
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6.Just looking at the map, would it be easier to
head down from the peak going East, or going
North?
N
E
C
D
B
W
E
1200m
F
1000m
A
800m
400m
600m
S
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Answers!

• 1. No The elevation must be under 1400 meters,
  but over 1300 meters.
• 2. about 400 meters

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Answers!

• 3. (A) is probably close to the 750 meter line,
  (B) is above 1300 meters. The difference between
  the two would probably be 650 to 700 meters.

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Answers!

• 4. No It must be more than 700 meters and less
  than 800 meters.
• 5. Down a valley If the contour lines point up
  the slope its a valley, if they point down the
  slope its a ridge.

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Answers!

• 6. East When contour lines are close together
  that means there is a steep slope, the further
  apart the lines, the more gentile the slope and
  therefore an easier walk! Go east!