There are lots of public data sources that report at a ZIP code level.
Of course, I can use crosswalks to relate ZIPs to ZACTAs,
but I'd really like to allocate ZIP data onto Block Groups geographies.
Is there a best practice for projecting dissimilar geographies onto one another?
(using shape files and their proportional overlaps?)
Zips are pretty big to crosswalk to block groups (62 zips in all or part in Chicago). HUD distributes zip-to-tract and tract-to-zip crosswalk files at their web site. Get the right ones for the 2010s and the 2020s.