Open source
χGRIDs
What if Chicago had a spatial unit that was exact, uniform and addressable, beneath the fuzzy neighborhoods?
Chicago Geographically Reductive Indexed Districts tile the city into roughly
one-mile cells named by their offset from State and Madison, so χ:5S3W is the
Damen–43rd chi. The repository holds the methodology, the polygons and the
generators, in several versions with different geometry.