Thematic Map

Thematic maps are maps that relate a single theme or purpose. An example would be a map that demonstrates voting demographics by political party (red state, blue state). This particular thematic map represents the fertility rates (Children per woman) throughout the world. The darker colors are higher fertility; all countries are represented on a color scale from darkest to lightest. This is also an example of a choropleth map.

http://blog.thematicmapping.org/2008/03/first-thematic-map-examples.html