I'm wondering if anyone can nudge me in the right direction. I'm trying to divvy up ACS congressional district data (116th session) into 118th session districts (since 118th isn't available yet). Is there something like a crosswalk file that accomplishes this already? I've done some searching but haven't come across one yet and am hoping I'm just overlooking it. I've currently created a union of the spatial files of the two sessions, but still need to apportion some 116th district polygons because they overlap 118th boundaries.
You could use Geocorr:
I agree Geocorr is a great resource for this, but I'd strongly recommend against a simple 116th to 118th crosswalk if you can avoid that. Instead, I'd crosswalk from smaller units to 118th CDs... blocks…
FYI--The Census Bureau released 2021 ACS 1-year Data Profiles for the 118th Congressional Districts at www.census.gov/.../.
I agree Geocorr is a great resource for this, but I'd strongly recommend against a simple 116th to 118th crosswalk if you can avoid that. Instead, I'd crosswalk from smaller units to 118th CDs... blocks, block groups, tracts, county subdivisions... whatever the smallest areas are for which you can get the data you need. Any of these areas nest much better within 118th boundaries, and therefore allow you to aggregate up confidently, rather than disaggregate from 116th areas--resulting in needless estimation error--anywhere they're split by 118th boundaries.We discuss this general principle on the IPUMS NHGIS crosswalks page here, but NHGIS crosswalks don't directly support bridging to 118th CDs. The Geocorr relationship files do.Then again, if the data you're working with are available *only* for 116th CDs, then yes, a direct crosswalk is reasonable. You could still try some more advanced allocation approaches, but weighting by the population counts that Geocorr provides should work well enough in most cases.
Good points Jonathan Schroeder -- I was mostly going to the crosswalk question