Reading a topographic map

Reading a topographic map

• 1.
  Reading a Topographic Map
• 2.
  What are topographicmaps used for?
• 3.
  Topographic Maps: • Showsurface features of the Earth such as mountains, valleys, craters, lakes, etc • Show elevation (height above or below sea level)
• 4.
  A picture ofelevation: Sea Level
• 5.
  How to Reada Topographic Map: Contour Line: • Connect points of equal elevation • Each line represents a change in elevation
• 7.
  Contour Interval: • Theamount of elevation between 2 contour lines. Example: If the contour interval on this map is 10 feet, what is the elevation of “A”?
• 8.
  Relief: The difference betweenthe highest and lowest point on the map. What is the relief on this map? (Remember the contour interval is 10 feet)
• 9.
  Index Contour: Darker, heavierlines – usually about every 5- 10 lines. These are often the only lines labeled
• 10.
  Golden Rules ofReading Topographic Maps: 1. Contour lines NEVER cross 2. All points on one contour line represent one elevation 3. Closely spaced contour lines mean steep slope 4. Contour lines that are far apart mean gentle slop or flat land
• 12.
  5. Contour linesthat cross a valley or stream are v-shaped a.The v points to higher elevation b.The v points upstream Example:
• 13.
  6. Contour linesform closed circles around hills, mountains, and depressions
• 14.
  7. Depressions aremarked with short straight lines inside the circle Example:
• 15.
  You Try It… Drawa topographic map for a “pretend landscape” that has a relief of 200 ft, 2 hills, 1 depression, a river, a city, and some wooded areas. Use a contour interval of 20 ft.