1. Where is this?
The cell

2. Where is this?
woodfield

3. Where is this?
wrigly

4. Where is this?
Assembly hall

5. Where is this?
White House

6. Where is this?
Grand Canyon

7. Where is this?
Rocky Mountains?

8. Where is this?
Yosemite

9. Where is this?
Shiprock New Mexico

10. Where is this?
Mt St Helens

11. How would you represent these, or any other landform, on a map?
In other words, is it possible to show a three dimensional object on a two dimensional piece of paper?

12. Topographic Maps

13. What is Topography
The shape of the land

14. Elevation Height above mean sea level (0 ft.).
point midway between the highest and lowest tide levels of the ocean.

15. Topographic Map
Show surface features (natural and constructed) and the shape of the land (topography) using lines of equal elevation (contour lines).

16. Contour Lines Show elevation
Each contour line connects all points on the map that have the same elevation.
Are brown in color
Nothing to do with distance or direction
Not an even distance between each line

17. As the water rises it leaves a shore line of equal elevation all around the island.

18. Each marked line on the island represents points of equal elevation.

19. Examples

23. Contour Interval
The difference in elevation between one contour line and the next.
715’ – 710’ = 5’
Contour lines have NOTHING to do with distance!
710 ? ?
715

24. Index Contours - Bolded contour lines that have the elevation marked on them Every 5th contour line F G D B C A E
What is the contour interval for this map?
What are the elevations of the marked points?

25. Relief
A cartographer (map maker) chooses a contour interval based on the relief of the land.
High relief = large contour interval
Small relief = small contour interval
Large relief = dynamic topography
Small relief = flat land
What would the relief be for this map, if these numbers were true?
Highest elevation – lowest elevation X
710 X
750

26. Three Basic Rules of Contour Lines
#1 The elevation on either side of a contour line is either higher or lower than the contour line itself
What is the contour interval for this map? 75
100
125

27. Basic Rules Continued….
#2 Contour lines never cross
What is the elevation at this point????!!!!
200
100

28. Basic Rules Continued….
What is the elevation at this point????!!!!
#3 Contour lines never split
100
101 99
100 99
101 99
101
100

29. Landforms on Topographic Maps
Hills are represented by a series of closed contour lines
Depression contours are indicated by hachure marks on the downhill side.
Contour lines “V” upstream when crossing a stream. The point of the “V” points uphill.

31. Reading Elevations

32. Some of the more common and important topographic map symbols have been pointed out by the purple arrows.  More details are given in the text below. 

33. USGS Benchmarks

36. Gradient

37. Why does the road bend so much?

40. Gradient – change in elevation over distance
Reading Gradient

41. Calculating Gradient