This is one of the most basic types of graphs, simply a data se of two varibles graphed in terms of each other. This one looks at the quality of a class vs. its credit value taken by students at Coumbia University.
Found - http://www.stat.columbia.edu/~cook/movabletype/archives/scatter.png
This blog is a map catalog in which I am displaying fifty different types of maps and a tid-bit of information that looks into the purpose of the map!