Bivariate Choropleth Map

A bivariate choropleth map shows two variables on the same map. The information is represented by two different symbols and shows the relationship of the variables.

The example map shows which canidate won each of the 50 U.S. States during the 2008 election.

Reference URL: http://voices.washingtonpost.com/ezra-klein/2010/04/the_red_state_ripoff.html