If you are willing to pay money, tools like AmMaps and Tableau can fill the "pre-assembled" requirement. For free, you can use the Many Eyes project to do this

If you are willing to pay money, tools like AmMaps and Tableau can fill the "pre-assembled" requirement. For free, you can use the Many Eyes project to do this kind of visualization as long as you can transform your data source into the required format. There was also a neat proof of concept that someone from the OpenLayers community did a while back: http://crschmidt.net/mapping/choropleth.html http://crschmidt.net/mapping/choropleth.html I've used that code in my Mozilla Metrics to generate some nice choropleth maps. Finally, there is the code that I worked on as part of the Mozilla downloadstats visualization. It reads a JSON feed of locations and puts markers on a Canvas map. http://www.mozilla.com/en-US/firefox/stats/ http://www.mozilla.com/en-US/firefox/stats/ https://svn.mozilla.org/metrics/downloadvis https://svn.mozilla.org/metrics/downloadvis