# topographic maps topographic maps. what are topographic maps? topographic maps- maps that show...

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• Slide 1
• Topographic Maps TOPOGRAPHIC MAPS
• Slide 2
• What are topographic maps? Topographic maps- maps that show changes in elevation of Earths surface Elevation- distance above sea level. Also show mountains, rivers, forests and bridges
• Slide 3
• Contour Lines Contour lines- connects points of equal elevation.
• Slide 4
• One Island.Two Views
• Slide 5
• One IslandTwo Views
• Slide 6
• Identify the Elevation
• Slide 7
• What is a contour interval? Contour interval- the difference in elevation between two side by side contour lines What is the difference in elevation between these two lines?
• Slide 8
• What are index contours? Index Contours- contour lines that have marked elevations. Can use them to find the contour interval Index Contours
• Slide 9
• Finding the Contour Interval 1.Find the index contours. 2.Determine the elevation difference between the two index contours 800 m 700m = 100 m 3. Count the number of spaces between the 2 index contours. 5 4. Divide the elevation difference between the 2 index contours by the number of spaces. 100 m / 5 = 20 m.
• Slide 10
• Scale Scale is the relationship between horizontal distance on the map and distance on the ground.
• Slide 11
• Three types of scale
• Slide 12
• Slide 13
• Slide 14
• CONTOUR MAPPING RULES Do Worksheet 1-6
• Slide 15
• 1. A contour line represents a single equal elevation, all points on the contour line have the same elevation.
• Slide 16
• 2. Contour lines do not cross other contour lines.
• Slide 17
• 3. Where one closed contour line surrounds another, the inner contour line represents the higher elevation. Which line has the higher elevation?
• Slide 18
• 4. Every 5 th contour line is darker and has the elevation marked. These are index contours.
• Slide 19
• What is slope? Slope- change in elevation over a given horizontal distance Formula for slope Slope = change in elevation horizontal distance Which hill has a steep slope? Gentle slope?
• Slide 20
• 5a. On a contour map, closely spaced lines indicate a steep slope.
• Slide 21
• 5b. Widely spaced lines indicate a gentle slope
• Slide 22
• 5c. Uniformly spaced lines indicate a uniform (constant) slope. Notice that the contour lines for each are the same distance apart in each picture. There is the same change in elevation for each given distance.
• Slide 23
• Comparing Slope
• Slide 24
• 6. A contour line that closes within the limits of a map indicates a hill, ridge or plateau.
• Slide 25
• 6a. Highest possible elevation of a hill is just below the value of the next contour line that would be drawn. The last contour line drawn is 220 m. The next line would be 240 m. Since there is no 240 m line, the hill cannot be higher than 239 m.
• Slide 26
• 7. Depressions are shown by small marks (hachures) pointing inward off the contour line. Elevation of the depression would be less than 140 m.
• Slide 27
• 8. Where a contour line crosses a stream or valley, the contour bends to form a V to point upstream.
• Slide 28
• Exit Card Without looking at your notes, write two things you learned today. Write one question you have about topographic maps. It can be something that confused you or something youd like more information about.
• Slide 29

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