NHGISJOIN variable in the 1870 county boundary files



I’m trying to use the 1870 county boundary files to create maps based on the ICPSR county-level data. I couldn’t find the actual NHGISJOIN codes anywhere on the IPUMS website, but I was able to infer your method of computation. Everything worked well except for areas that were still territories in 1870.

I see that for territories you substituted a “5” for the “0” in the third position from the left in the seven-digit code. Fine. I made that change to my county data codes. I also see that the NHGISJOIN county codes for territories in 1870 are different from your standard county codes. So, for example, in 1870, Boise County, Idaho’s NHGISJOIN value is 1650075. If you were using the standard county codes presented on the IPUMS website, and forgetting about the “5” in the third position from the left, that code should have been 1650150. Fine there as well. Although the process is cumbersome, I can create a mapping between the standard values and the special ones for 1870.

Even after I have made all these adjustments, my mapping program, Golden Software’s Mapper, won’t map data for territorial areas. Perhaps this is a problem with Mapper. Just a soon as I get this message off to you I will write to Golden Software with my question as well. But if you see any errors in my logic or procedures as described above, I would be very grateful for your corrections.

Thank you in advance for any assistance you can offer. I really appreciate your efforts.

All the best,