Classed Choropleth Map

http://personal.uncc.edu/lagaro/cwg/color/color_symbol.html

A classed choropleth map shows data in a specific class by coloring in the proportional area on the map. A choropleth map provides an easy way to visualize how a measurement varies across a geographic area. This is a map that shows the amount of expenditure per pupil county by county in North Carolina. If you read the box it actually says that this is a poor exampe of a choropleth map because the hues of color that reperesents the different classes of data are too close together to distinguish. This brings up an interesting point when thinking about class choropleth maps. The idea behind them is to make it much easier to read the graph  visually but the colors have to be distinguishable.