Wednesday, March 07, 2007

Free Historical Census Data: 1970, 1980, 1990

Received a request over the weekend for 1990 Census data on the block level beyond what is currently available through our local holdings. We are purchasing the CensusCD 1990 Blocks from Geolytics, but in the meanwhile this forced me to take some time exploring free historical Census data availability and so here are the results of what I discovered.

U.S. Census Bureau
  • Data Files: Census 1980
  • Data Files: Census 1990
    • These downloadable data files are fantastic in that users can freely download the entire 1980 and 1990 dataset, including all the summary tape files (STF). Downside is they are not easy to use. Choice is to install the Extract software or access the DBF files yourself. In the past I imported the DBF file containing the STF 1B for Texas into an Access database and made that database available to our library users, who would then run queries against the data. (Access, of course, will be much improved when we acquire CensusCD 1990 Blocks.
  • American Factfinder
    • Everyone loves this fantastic resource, but it only offers data from 1990 and 2000. Their 1990 holdings do not contain STF 1B, and so do not go down to the block level.

University of Wisconsin-Madison Center for Demography and Ecology
  • 1970 Census Summary Tape Files
    • Files for all available states and the District of Columbia for the 1970 4th Count A and C population and housing files may be downloaded.
  • Current Population Surveys (various, from 1963 - 1990)
  • 1980 Public Use Microdata Sample (PUMS)

UC Berkeley Social Science and Government Data Library: Files to FTP
  • Been having trouble accessing their public archive, which is too bad as it has been a fantastic resource. Seems as if their FTP server dis not permitting public anonymous logon. Their FTP server is permitting anonymous logon, but does not contain their data. Hopefully their data will be made available to the public again.
Interuniversity Consortium for Political and Social Research (ICPSR)
  • This is not a free resource, but it seems silly comprising this list without mentioning the ICPSR. Many (if not most) academic universities should be a member of ICPSR and have access to its data holdings.
  • Here are their Decennial Census holdings.

Saturday, March 03, 2007

Public Transportation Workshop a Success!

Here is an example of a bus route developed by a workshop participant.

20 folks attended to hear Dr. Anjomani discuss student endeavors to plan transportation routes and to then plan their own during this hands-on GIS workshop. For more information about this workshop, see this previous post.

Everyone had a lot of fun, bunch of folks stayed afterwards with questions, and I am already booked to repeat the workshop next week specifically for the City & Regional Planning GIS folks. Everyone generated their cost matrices, used some on-the-fly weighted mean techniques to position the stops, and then created the bus route. Then, of course, the script called ArcMap2GMap to overlay the stops and route via Google Maps.

As an added bonus, the event was covered in The Shorthorn, our student-run newspaper (see image). Click here (pdf) to view the entire issue from Friday, March 2.

As I promised earlier in the week, the workshop materials, including the Python scripts, can be downloaded here. This is actually the zipped contents of the CDs that each participant received. Unzip the contents and launch the Public_Transportation_in_Arlington_Plan_the_Route.exe file (which would have auto-run if you had the CD). ArcGIS 9.1 is required. It might work with 9.2, but I have not tested it.