Isolines, also known as contour lines, connect points of equal value on a map. They are used to depict characteristics such as elevation, temperature, rainfall, and pressure. Isolines are always closed, do not cross, and indicate a rapid change where lines are close together and a gradual change where lines are far apart. Common types of isolines include contour lines for elevation, isotherms for temperature, and isobars for atmospheric pressure.

1. Isolines and Contour Lines

6. http://www.ux1.eiu.edu/~cfjps/1400/chapter3.html

9. http://www.middleschoolscience.com/isotherms.htm Extra Credit Opportunity: Draw in the isolines for 5 points

14. Simple Contour Line Map and Profile http://raider.muc.edu/~mcnaugma/Topographic%20Maps/contour.htm