Univariate Choropleth Map

Source - http://www.colocarto.com/custom-thematic-maps.html

Here we have a univariate choropleth map that measure only a single variable on a map, unlike a bivariate that measures two variables at a time. This map measure the estimated median household income for 2008 of the United States. These kinds of map are easy to read becuase of the simplistic amount of information on them. As you can see there is a key to tell you what color match what income rate. The pattern of the map is that the west seems to have a better estimated median income than the east does for 2008.