I'm writing a program that needs to generate GEOID values from 2000 and 2010 Census data, to link the census data to TIGER/Line records. I'm starting with the state, county, region block, etc, values in the census GEO files, and need to create GEOIDs.
I need to work with all of the summary levels, and since the structure of the GEOID value seems to vary depending on the type of geography, it would be really nice to have a spec for constructing it.
I found this document, but it only specifies the GEOID structure for the redistricting files:
http://www.census.gov/rdo/pdf/0GEOID_Construction_for_Matching.pdf
I'd like to get the same thing, but for all summary levels.
I've considered downloading all of the tiger files and extracting the GEOID10 values and reverse engineering them from the records attached to the shape files, but the programming would cost more than just paying someone to do it manually by inspecting the files or the documentation ( http://www.census.gov/geo/www/tiger/tgrshp2010/TGRSHP10SF1.pdf )
Any other ideas how to most easily generate GEOID from census GEO files, for all records and summary levels?
Alternately, can the 0GEOID_Construction_for_Matching.pdf file, which is written for the redistricting files, be used as a spec for the 2010 SF1 summary levels and the GEOIDs of the corresponding TIGER files?
Best Answer
The GEOID is a concatenation of a bunch of fields as noted in the summary file documentation on page 13. In the geographic area codes, you'll be looking for fields at positions 26-65.