1. Mapping Earth Midterm Review
Topics:
Isolines
Drawing isolines
Topography (Reading Contour maps)
Finding Interval
Hills
Steep/gradual slopes
Gradient
River Direction
Maximum/minimum elevation
Depressions (hachured marks)
Profiles

2. Isolines Connect points of equal value Isotherm: temperature
Isobars: barometric (air pressure)
Contour lines: elevation

3. Drawing Isolines Connect the points with the same value
Estimate between which other values the line should be drawn
Lines should be curved, not angular
Extend lines to edge of map
Never cross isolines

5. Topography (Contour maps)
1-dimensional representation of a 3D landscape
Shows the shape of the land

6. Finding Interval Difference between one contour line and the next
May be given on map
Labeled lines are Index Contours

7. Subtract the value of two consecutive Index Contour Lines
Then count how many contour lines there are from one Index Contour to the next (only count one of the Index Contours)
Divide the difference by the # of lines
=100m
5 lines
100/5= 20m

8. Hills
Hills or mountains are shown by contour lines that form closed loops

9. Steep/gradual slopes Steep Slope: contour lines are close together
Gradual Slope: contour lines are far apart

10. Gradient Difference in Elevation Distance between two points
Label with given units!

11. River Direction
Contour lines bend upstream

12. Ocean is Sea Level = 0 elevation

13. Depressions (hachured marks)
The first hachured line is the same value as the last contour line.
Each hachured line decreases by the contour interval

14. Ocean=
Interval =
1st Hachured line = 20
Elevation at point A= 10 10

15. Inferring Maximum/minimum elevation
Max: Value just below what the next contour line would equal Z=
Min: Value just above what the next contour line would equal Y= Z
99 ft
21 ft Y

16. Maximum Elevation
Represented by Triangle symbol

17. Profiles Cross section (side view) of the contour map
Use mark and slide method
Keep a STEADY hand
No numbers on x-axis
Use contour interval on
Y-axis

20. What is the contour interval? SE
What is the max elevation at point E?
What direction is Mud Creek flowing?
139 20
What is the contour interval? SE