1. Topographic Maps

2. Essential Questions What do topographic maps depict?
How are they constructed?
What are contours and isopleths?
How can they be used to understand the Earth, and Earth processes?
What’s the difference between a topographic map and a bathymetric map?
Can other data sets be contoured?

3. Topography How maps show topography Hachure Isopleths
Hypsography (water flows)
Shading
Contours

4. Hachure

5. Isopleths & Hill Shading

6. Hypsography (water flows)

7. Contours

8. Contour Lines All points along a contour line are the same elevation.
Contour Interval is the elevation change between adjacent contour lines.
Most maps have major contour lines at a regular interval that are labeled with their elevation.

9. Contour Properties
The closer together the contour lines, the steeper the slope.
The fall line, or “straight down the hill” is perpendicular to the contour lines. This is the direction water would flow.
Water flows downhill and is a major force in shaping the topography.

10. Understanding Contour Lines
The key to making contour lines useful is learning how to translate from the “bird eye view” on the map, to what you see and experience as you hike through the terrain.
What will you see?
Will you be going uphill or down?
How steep will it be?
How will these things change as you move along your path?

11. Recognizing Basic Features
Hilltop, Mountain, Peak
Drainage, Canyon, Valley
Bluff, Cliff
Ridge
Saddle, Pass, Cut

12. What is the highlighted feature?
How do you know?

13. What is the highlighted feature?
It’s a hill top, summit, or peak.
How do you know?
The small “circle” contour
lines are high points.

14. What is the highlighted feature?
How do you know?

15. What is the highlighted feature?
It’s a saddle, or pass
How do you know?
The “hourglass” shape with
higher terrain on either side.

16. What is the highlighted feature?
How do you know?

17. What is the highlighted feature?
Steep terrain, possibly cliffs
How do you know?
Contour lines are very
close together.

18. What is the highlighted feature?
How do you know?

19. What is the highlighted feature?
It’s a wide flat valley
that gently slopes up to
the NW.
How do you know?
Contour lines are far apart
Terrain rises on either side
Water runs down the middle
Higher contour lines to the NW

20. What is the highlighted feature?
How do you know?

21. What is the highlighted feature?
It’s a ridge line.
How do you know?
A string of summits
all in a line
Terrain drops off on
both sides

22. What are the highlighted features?
How do you know?

23. What are the highlighted features?
Intermittent streams
How do you know?
The blue line with dots
The V like contour lines
with the “sharp” end
pointing upslope and
towards a summit

24. What is the highlighted feature?
How do you know?

25. What is the highlighted feature?
It’s a ridge or finger
How do you know?
U or V shaped contour lines
pointing down slope.
Terrain drops off on both sides.
It’s between two drainages.

26. What is the highlighted feature?
How do you know?

27. What is the highlighted feature?
It’s a drainage
How do you know?
V or U shaped contours
pointing uphill.
It “flows” into another
stream or drainage