Nominal area choropleth map

http://www.veiled-chameleon.com/weblog/archives/2004_07.html A nominal area choropleth map is a thematic map that uses colors or patterns to distinguish between the measured data.  What separates these from the rest is the fact that these maps use nominal data or data that is qualitative, not quantitative.  These maps usually do not contain numbers and are used to show differences across states or countries.  This map shows the differences in political party choice among the U.S. states