1. Topic 3: Measuring Planet Earth
Part 3.5: Fields, Isolines and Gradient AIM: Describe the purposes of the different lines used on maps.

2. 1. What is a field?
A region of space that has some measurable value of a given quantity at every point

3. 2. What is an isoline?
A line that connects points of equal value

4. 3. What is an: Isotherms - lines that connect points of equal
temperature

5. 3. What is an: Isobar – lines that connect points of equal air
pressure

6. 3. What is an: Contour lines – lines that connect points of
equal elevation

7. 4. What is contour interval?
the difference in elevation between two consecutive contour lines

8. 5. What is gradient?
Slope
The average rate of change from place to place within a field

9. 6. What is the formula for gradient?

10. Examples:
A weather map shows a change in temperature of 12⁰ C between two locations that are 3km apart.
What is the gradient?

11. Distance from Point A to Point B is 40 kilometers
Find the gradient between point A and point B:
Distance from Point A to Point B is 40 kilometers

12. Lab Demo- (we will do this lab in class!)

13. 7. What does the spacing between isolines tell you about the slope (gradient)?
The closer together the isolines , the
greater the slope (gradient)