There is a package for "R" that allows you to work with geographical
maps (at least US state/county maps). I haven't looked into it in
detail but at the very least you can select the shade of each object
based on a value so it works great for depicting densities across
geographical areas. There is a similar plug-in for Excel if you are on
Windows (which I'm not). Does nayone know of anything like that for
Stata?
