What software is used for maps of the US (or other arbitrary areas)?

Question

What software does one use to create a map that describes conditions over an arbitrary area ? The example I am thinking of would be a map of the US where states that voted one way or another would be red or blue. Obviously I can get a map of the US and use a graphics program to manually paint in the states, but I am figuring there should be some sort of software to do that in a somewhat automated fashion. Apart from a for-pay web app, I haven't been able to find anything. I am very new to the field so I'm not familiar with the available tools.

Answer 1

In addition to the package that @robin pointed too, you should look at the Spatial Task View on CRAN. What you are describing is known as a choropleth map, as illustrated here: Choropleth Maps of Presidential Voting, or U.S. Unemployment Data: Animated Choropleth Maps.

In R, they can be handled using

• the base graphics routines (with maps),
• the lattice way (see mapplot() in latticeExtra),
• the ggplot2 way (see e.g., Choropleth Challenge Results for example code).

Other softwares that allow to deal with geographical maps include Mondrian, Quantum GIS (and I guess many other GIS programs), but data format may vary from one software to the other.

Answer 2

You should try R software with package spdep. see the vignette here

Answer 3

I've not tried CrackMaps but it looks very interesting. Only available for the Mac, I presume.

Answer 4

Self promotion: JMP (commercial desktop software) does choropleths of US states, US counties, world countries and regions of select other countries.