1. What are they? Why are they useful? How do you read one?
Topographical Maps
What are they?
Why are they useful?
How do you read one?
Thumbs up if you know how to read a topo map
Thumbs middle if you know what a topo map is but not how to use one
Thumbs down if you’ve never heard of topographical maps

2. Topography
Refers to the human and physical surface features of an area
Topo maps have contour lines that show elevation
Sometimes called “contour maps”

3. Rules for Reading and Creating
Mean sea level is an elevation of 0 feet
Every point on a contour line has the same elevation above sea level
Always check the map for the contour interval in use
What is our elevation here? Elevation at the bottom of the canyon?
Talk to neighbor about question (interval is 50ft)
What is the contour interval for this map?

4. Rules for Reading and Creating
Contour lines never cross one another
Contour lines are closed figures
Small, closed loops indicate hilltops
Ridges are hills that are long and narrow

5. Rules for Reading and Creating
Spacing of contours depicts slope
Relief is variation in elevation and slope

6. Rules for Reading and Creating
Where streams are shown on a map, the contours always form a V or a U shape with the apex pointing upstream (higher)

7. Rules for Reading and Creating
Hatchure lines represent a depression. They point in to the lower elevation.

8. Rules for Reading and Creating
Benchmarks are exact elevations
… and by a brass plate on the ground
Marked by an X on the map….
Elevations indicated precisely are spot elevations or benchmarks. Spot elevations have been checked by surveyors..

9. Slope Hill Valley Ridge Depression Saddle What are these features?
Slope (Brown)
The steeper the slope, the closer the contours, because it takes less distance to rise or fall a given amount on a steep slope.
Hill (Yellow)
Contours are concentric with maximum elevations in the center
Valley (Blue)
Lower elevations in the center. Contours form V's that point upstream.
Ridge (Green)
An elongate hill. Elevations high in the center. Contours form V's pointing downhill.
Depression (Red)
Uncommon, and usually shown with hachured contours. The hachures are on the downhill side.
Saddle (Purple)
The landform that confuses more beginners than any other. Land slopes downhill in some directions, uphill in others. Any time you have four elevation points, with the points on one diagonal high and the other low, you probably have a saddle.

10. Draw its profile

11. Draw its profile