1. Visualizing Earth’s Surface

2. Maps: Represent a portion of the Earth’s surface
Maps: Represent a portion of the Earth’s surface. Different maps are used to show different information about the Earth.

3. A. Types of Maps:
1-Weather

4. 2.Geologic: Shows rock formations and soil compositions.

5. 3. Road: Shows roads, towns, and cities.

6. II-Field Maps: A map on which similar measurements are plotted
Examples: could be temperature, pressure, or elevation.
A- Isolines - Connect points of equal value on a field map.
“Iso-” means same

7. Examples of Field Maps
2- Isotherms - Lines connecting equal temperatures
1- Isobars - Lines connecting equal pressures
3- Contour Lines - Lines connecting equal elevations

8. B- Topography: general form and shape of the land on Earth’s surface (mountains, valleys, streams, ect)

9. C- Topographic Maps - -show the shape of earth’s surface
-isolines on a topographic map are called contour lines
- Contour lines show points of equal elevation

10. 1- Index Contour Lines
- Heavy lines spaced at a predetermined elevations on a topographic map.

11. Benchmark – tells the real elevation at that point
2- Contour Interval- The vertical distance that separates each contour line on a topographic map.
Benchmark – tells the real elevation at that point

12. -Closed contours on a map as an ellipses or circles represent hills.

13. hachure marks represent depressions (holes).
-Closed contours with
hachure marks represent
depressions (holes).
Contour Interval = ?

14. The contour line with the
marks, or hatchers, has
the same elevation
as the line before it.

15. From a higher elevation to a lower elevation
Water flows down hill
From a higher elevation to a lower elevation

16. (water flows in the opposite direction)
-When a contour lines cross a river they make a “V” that points upstream.
(water flows in the opposite direction)

17. III- Rules for Contour Lines:
A contour line represents a single equal elevation: that is, all points on the same contour line have the same elevation. 5 5 10 10 10 10 15 15

18. 2. Where one closed contour line surrounds another, the inner contour line represents the higher elevation.
Lowest
elevation
0 m
400 m
Highest
elevation

19. 3. The elevation represented by a contour line is always a simple multiple of the contour interval. (5, 10, 50, 100)
0 m
100 m
200 m
300 m
400 m

20. A contour line that closes within the limits of the map indicates a hill, ridge or plateau.

21. 5. On the same map, closely spaced contour lines indicate a relatively steep slope, widely spaced contour lines indicate a relatively gentle slope.
Steep
Gradient
Gentle
Gradient

22. 6. Contour lines do not cross other contour lines
6. Contour lines do not cross other contour lines. Exception: on a vertical cliff or a nearly vertical cliff, contour lines touch because they are on top of one another
Cliff

23. 7. Every contour line eventually closes against itself
7. Every contour line eventually closes against itself. However, the map area may not be large enough to show this closure. Therefore, the contours will end at the edge of the map.

24. 8. Closed depressions are shown by hachured contour lines
8. Closed depressions are shown by hachured contour lines. The hachures point into the depression. (Hachures = short dashes)

25. 9. A hachured contour line, lying between two different contour lines, is the same elevation as the lower contour line.
Count down
Count up
Contour
Elevation
Repeats

26. 10. Where a contour line crosses a stream or valley, the contour bends to form a “V” that points upstream or up the valley.