1. Topographic Maps

2. Topographic Maps
A topographic map shows the elevation of an area on Earth
Topographic maps allow you to see a three-dimensional landscape on a two-dimensional surface

3. Topographic Maps
Topographic maps typically have a scale of 1:24,000 (which means that 1 inch measured on the map represents 24,000 inches on the ground)

4. Contour Lines Elevation is indicated by contour lines
A contour line is a line of equal elevation
All points on a contour line have the same elevation
Contour lines never touch or cross

5. Contour Lines What do these concentric circles represent?
A peak (hill, mountain, etc.)

6. Consider an Island . . .

7. Consider an Island . . .
Contour lines are like imaginary shorelines

8. Contour Lines

9. Slope
You can tell how steep the terrain is by how close the contour lines are to one another
If contour lines are close = steep slope
If contour lines are far apart = gentle slope

10. What is the elevation at points X?
X(a) – 540 m
X(b) – 580 m
X(c) – 600+ m

11. Match the Contour Lines to the Topographic Profile

12. Water Flow DOWNHILL! Which direction does water always flow?
Water always flows perpendicular to contour lines (i.e. downhill)

13. Which direction will water flow?

14. Topographic Map Rules
Lines that are close together indicate steep slopes
The area circled in red is very steep, because it has many lines crowded close together
Lines that are far apart indicate gentle slopes
The area circled in blue is not steep, because it has lines that are spread far apart

15. Topographic Map Rules
Since contour lines must remain at the same elevation, they bend when they cross riverbeds
A riverbed drops downward, so the contour line must bend upstream to stay at the same elevation
When contour lines cross a stream, they form a “V” that always points uphill

16. Watersheds
A watershed is the area of land where all of the water that drains off of it goes into the same place

17. Delineating a Watershed
Mark the area of interest
Mark the high points adjacent to the area of interest
Starting at the area of interest, draw a line connecting all of the high points on one side of the waterbody
Watershed lines must ALWAYS cross contour lines perpendicularly

18. Delineating a Watershed

19. Delineating a Watershed

20. Practice Problem #1 Answer

21. Practice Problem #2 Answer