1. Do Now:
Write down 3 observations about this map.

2. Learning Objective:
I can draw isolines on a map.

3. Isolines
A line connecting points of equal value.

4. Examples of isolines: The weather channel loves isolines! Isotherms:
points of equal temperature
Isobar:
points of equal air pressure
Contour:
points of equal elevation
The weather channel loves isolines!

8. Rules for Drawing Isolines:
1. Isolines connect points of equal value. 5 5
10
10
10
10
15
15

9. 2. Are gentle, curving lines- no sharp corners.5 5
10
10
10
10
15
15

10. 3. Are always closed curves even though the map might only show part of it.

11. 4. NEVER cross- this would mean that one point has two different values.
60 °
50 °
40 °
30 ° X
20° Z Y

12. 5. Isolines usually are parallel. (They have a parallel trend.)

13. Time to Practice:
Using the data points draw isolines with an interval of 10 meters.
Use a pencil….its ok to make mistakes.
By the end of this assignment you will have met todays learning objective.

14. Highlight data points.

15. Fill in gaps in data.

16. Connect the dots.

17. Go on to the next value.

18. Summary: How do we draw isolines?
What are two things isolines must do?

19. Gradient
Gradient shows how quickly the value changes from one point to another.

20. A gentle (low) gradient changes slowly and the lines are far apart.
A steep (high) gradient changes quickly and the isolines are close together.
A gentle (low) gradient changes slowly and the lines are far apart.
Steep area
Gentle area

21. Making a Contour Map II

23. Drawing Contour Maps III