Unclassed Choropleth Maps

http://www.princeton.edu/~rvdb/JAVA/election2004/purple_america_2004_small.com

 Unclassed Chorpleth maps are maps that use proportional shading to show the difference in a measurable variable. These maps are unclassified because they do not declare set of 5-10 or so ranges of shades and matching numerical values.  Instead, they have a full spectrum of shaded colors each with a corresponding numerical value. The map above shows the difference in political party choice across the US.  The freedom of shades allows for overlapping of colors to show a more accurate depiction, which in some places creates a purple shade.  In this map the more red a shade is, the more republican it is.  Likewise the more blue a shade is, the more democrat it is.