1. Chapter 3 Topographic Maps
Topography Means:
“Shape of the land”

2. Contour Lines Indicate areas of equal elevation
Will never cross or divide

3. Hill top
Circles within circles
Specific points are
called Benchmarks

4. Contour interval
Distance between contour lines
500’

5. Contour Interval
Contour Interval = 500’

6. Indicating all contour lines make it look cluttered – Index Contour Lines
To get C.I. : Take the Change in Elevation between two contour index lines and divide that by the number of lines between them. C.I. = 250’

7. You Try!!!
Map A
C.I. =
Map B

8. Benchmark: Exact elevation Marker

9. Close lines = steep slope

10. What do you think it looks like from the side?

11. Closed depressions on the land are shown by contour lines with “hachure lines” that point down slope.
(indicate holes or craters)

13. 6. A contour line forms a “V” shape pointing upstream when crossing
a river or stream. Downhill!!!
“V” Shaped
Contour Lines

14. Steep vs Gentle
River Direction

15. Gradient = Average rate of slope Determined by change in elevation divided by distance. Rise over Run!
Elevation Change (rise)=
Distance (run)= B A
Scale (km)
1km

17. A line that shows the changes in elevation
Topographic Profiling
A line that shows the changes in elevation
across a section of a topographic map.

21. Contouring: Elevation points have been determined using ground
surveying techniques or
GPS but contour lines need
to be drawn in.