Choropleth map

The Natioanla Highway Traffic Safety Administration :

http://www-nrd.nhtsa.dot.gov/departments/nrd-30/ncsa/STSI/6_CA/2006/6_CA_2006.htm

Above is a Choropleth map of California's 2006 alcohol related fatalities by county. A Choropleth map is a thematic map in which colored or shaded areas are in direct proportion to the measurement of the numerical or statistical information.