Standardized choropleth maps

http://upload.wikimedia.org/wikipedia/commons/thumb/7/78/USA_states_population_density_map.PNG/800px-USA_states_population_density_map.PNG

A Standardized Choropleth Map  is a Choropleth map that has its data standardized so it can be used for comparison. The map posted portrays the population per square mile by state using data form the 2000 census. This map is a standardized map because of its use of 2000 census figures.