Univariate Choropleth Maps

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

Univariate Choropleth Maps are maps that only analyze one variable. These maps are useful when looking at one topic because they present the data in simple means. The map above measures the estimated median household income in 2008. The map uses simple classification methods, but uses less detail. As the level of income goes up, the color of red becomes deeper.