1. How do topographic maps (contour maps) represent Earth’s surfaces?
Aim:
How do topographic maps (contour maps) represent Earth’s surfaces?

2. A topographic map (contour map) shows the surface features, or topography, of the Earth.
Most topographic maps show natural features (streams, rivers, mountains, hills,) and man made items, like buildings and roads.

3. What is Elevation?
Height above sea level.

4. What is a CONTOUR LINE?
A contour line connects all the points on the map that have the same elevation.
Lets say that these are all 100m elevations. Another
line would connect all the 200 m elevations, another for
300m elevations, etc. Giving us a picture of what the
land must look like.
notebk

5. What is a contour interval?
The difference in elevation between one contour line and the next.
80m
70m
Some maps may be 10m, 50m, 100m, 500m, 1000m etc.
Some maps may be measured in feet.
notebk

6. CONTOUR INTERVAL? Difference between consecutive contour lines! =100
In this case, the contour interval is:
=100
1200
1100
1000
900
800
700
600
500
400
300
200
100
notebk

7. What are INDEX CONTOURS?
Generally every 5 lines or so, there is a bold line. This is done for clarity and makes reading small maps easier.
notebk

8. Click on the area of this map that has the highest elevation.
What is the highest elevation here?
Where is the steepest slope located?

9. Yes ! this area is the highest
point above sea level. @
7,490 feet

10. What is the Relief?
Difference in elevation between highest and lowest points of the area being mapped.
Mt. Fuji
What is the relief here?
Contour interval?
notebk

11. Relief
-Amount of change in elevation from the highest point on the map to the lowest.
0 ft
= 500 ft.
(on this example)
500 ft

12. Each drawing violates a rule of contour lines. State the rule.

13. CLOSER CONTOUR LINES = STEEPER GRADIENT
TOPOGRAPHIC MAPS WOULD BE VERY CLUTTERED IF ALL CONTOUR LINES WERE LABELED, SO ONLY HEAVIER LINES SHOW LABELS

14. What is the pattern of the contour lines around a simple hill?
Concentric circles getting smaller - hill

15. What does a V-Shape indicate?
: In the case of rivers or streams,
The V’s will always point upstream!!
Water will flow from highest elevation to lowest
elevation

16. Streams
What shape is made with the contour lines when a stream is present?
upstream
“V” Shape
How do you know which way the stream flows?
The bottom of the “V” shape points upstream

17. Depression Contours In some cases, such as volcanoes, there may be a
Valley or “depression” on top of a hill or mountain.
A depression contour shows an area where elevation
is decreasing
This is shown by a contour line with dash marks:

18. Depression Contour Lines – indicate a decrease in elevation
What happens to elevation in the center of a volcano?
Elevation decreases
Depression Contour Lines – indicate a decrease in elevation
The first depression contour has the same value of last regular contour line

19. WHAT DOES THIS PROFILE SHOW?
VOLCANO
NOTICE HACHURE DEPRESSION LINES IN CENTER SHOWING VOLCANIC VENT

20. Identify the features marked at A and B