Census Geographies

After my outing last Sunday circumnavigating east Davis, I spent some time looking to see what information was available about Davis from the 2000 U.S. Census. I was quite pleased with the resources they have online, especially the interactive thematic maps linked from the American FactFinder site. This mapping tool allows you to make a map showing census information for any geographical level in the census system. The smallest unit in system is the census block, which is roughly equivalent to a city block. The next higher level is the block group, followed by the census tract. Those of you who filled the 2000 census may remember that there was a “short form” which most people filled out, requesting basic information about age, household size, housing status, and ethnicity, and also a “long form”, which about 1 in 6 people filled out, requesting additional information about employment, income, and so on. These maps allow you to depict information from the short form at the block level, and information from the long form to the block group level.

It’s a quite well-designed mapping interface, and has some nice cartographic touches such as allowing you to select the type and number of classification breaks to use in the theme legend. My one gripe was that the steps in the different zoom levels are too widely spaced: I kept trying to get all of the city of Davis to fit comfortably in the window at the block mapping level, but it didn’t allow me to do that.