Standardized Choropleth map

http://www.cdc.gov/pcd/issues/2007/oct/07_0091.htm

Standardized choropleth maps are used to show differences in variables, what makes them different is they keep the variable standard. This is a standardized choropleth map of poverty levels in the United States. Standardized choropleth maps are used to compare data, as you can see areas with high poverty are red, and dark red, while blue is low poverty.