Choropleth map

Choropleth maps are thematic maps that use a predetermined set of aerial units. These can be things such as states, counties, or even political boundaries. These maps are used when there is a need to show a statistical variable such as per capita income. Choropleth maps can be either classified or unclassified.

Link: http://www.clearlyandsimply.com/clearly_and_simply/2009/06/choropleth-maps-with-excel.html