MAPresso, developed by Adrian Herzog, is a free Java applet for making choropleth maps and cartograms. These kind of distorted maps equalize the surface of a certain country on the map with a particular feature (the population, for instance).

In the picture below: Italy, South Tyrol: Election results (elezioni provincali 2003) by the Civic Network.

Tags: anamorphosis maps, information visualization, map algorithms, maps