A python script to produce choropleths and colored square- and hex-grid maps
There are two classes, Chorobin to assign colors to quantities, and Chorogrid to make the maps.
Maps are made in SVG format; if you need to convert them to PNG you can do so in an external application like Inkscape or Adobe Illustrator, or in python with CairoSVG among other solutions.
Pro tip, because I made this mistake for a long time: it's "choropleth", not "chloropleth"; there's no L. The word comes from ancient Greek χώρα (khṓra, “location”) and πλῆθος (plêthos, “a great number”, same root as plethora), not χλωρός (khlōrós, “pale green”) as in chlorine and chlorophyll. Luckily Google knows enough to suggest the right one.