Ari Lamstein has updated his choroplethr package with a new capability for creating animated data maps. I can't embed the animated version here, but click the image below to see an animation of US counties by average household income, from the richest to the poorest by percentile. (The code behind the animation is available on github.)
The choroplethr package is also now available on CRAN, so you can install the latest version (including the new choroplethr_animate function) with the command install.packages(choroplethr) . In addition to playing animations from start to finish, you can also step though each frame using the + and - buttons.
This version of choroplethr was created during Trulia’s latest innovation week. Ari Lamstein wrote most of the R code, and the animation code was written by Brian P Johnson.
Google Groups choroplethr: choroplethr v1.4.0 is now available