I started using a great web site in my research. It is called The National Historical Geographic Information System. This web site provides aggregate census data, from 1790 to 2000, which you can download for free. With funding from the National Science Foundation, NHGIS has also made GIS shapefiles available at no cost on its web site.

I tried out this web site and found it really user friendly. One of the things it helped me with was uncovering patterns of racial segregation in major U.S. cities after 1940.

As I explored the web site further, I was really impressed with the range of data that is available from past censuses. The GIS capability made it even sweeter. If you don't know how to use GIS, the Social Explorer portion of the NHGIS web site provides an easy way to create basic maps.

I wonder if Thomas Sugrue used this sort of technology when he was producing _The Origins of the Urban Crisis._ Maybe not, since his book was published twelve years ago. In any event, his methods have inspired me to do some similar work. I even discovered a method for finding metropolitan census tracts with large numbers of American Indians in several pre-1970 censuses.

Sherman Jay Dorn - 6/3/2008

QuantumGIS (http://www.qgis.org/) is an open-source software for creating thematic maps. It sometimes takes a bit of editing of the data files, but it works, if all you need is thematic mapping.