Dear users of this forum,
I am trying to match IPUMS censusdata from 1860-1920 to the county subdivisions in a 2010 TIGER shapefile I downloaded from NHGIS. For some areas county subdivisions were stable from around 1860 to 2010 - that I have checked using historical maps and the names of the county subdivisions in the shapefile (for others not, of course).
Now, the GSIJOIN codes do of course not work since they are meant for merging the geographical units in the 2010 shapefile to 2010 census data. It would be great to at least find a common identifier for the counties in the two files since then I would only have to match the string names of the county subdivisions within the individual counties. As I understand the COUNTYFP10 (shapefile) and the COUNTY (census data) codes are not comparable. Is there any way to find out how COUNTYFP10 converts to the COUNTY code (however imperfectly)?
Any help on this would be greatly appreciated. Thank you!