TIF Project Data Sources

Data for the TIF Illumination Project was compiled from multiple sources:

City of Chicago:

* TIF Projection Reports: https://data.cityofchicago.org/d/zai4-r88e

Here is the reports from the investigation of the 27th Ward:

 

* Boundaries – Wards: https://data.cityofchicago.org/d/bhcv-wqkf

* Boundaries – Tax Increment Finance Districts: https://data.cityofchicago.org/d/iyec-2es5

* Boundaries – Building Footprints: https://data.cityofchicago.org/d/w2v3-isjw

* District Annual Reports: https://www.cityofchicago.org/city/en/depts/dcd/supp_info/district_annual_reports2011.html

Cook County:

* Property Info Portal: http://cookcountypropertyinfo.com

Additional data were acquired through various Freedom of Information Act (FOIA) requests, notably the tax code data that enumerates the percentage a taxing body takes from each property based on the taxing bodies’ overalapping jurisdictions.

The geospatial data (shapefiles) were loaded into a PostgreSQL (http://www.postgresql.org) database with the geospatial PostGIS ( http://www.postgis.org) extension (see OpenGeo’s excellent tutorial here: http://workshops.opengeo.org/postgis-intro). From there, buildings were matched to addresses so that any new data ¬†with an address could be matched to a building (which could then be matched to a TIF, which could then be matched to a ward, etc…).

Financial data from the District Annual Reports had to be manually entered, as they are all in PDF form and the necessary fields could not be easily extracted programmatically.

Through a FOIA request, we obtained every Property Index Number (PIN) in Chicago, with the total property tax amount billed to each of those PINs. Using http://cookcountypropertyinfo.com, PINs were matched to addresses, which were then geocoded by matching them to the buildings in the buildings footprint database (98.7% of non-vacant PINs were successfully geocoded). A spatial query could then be written to sum the property tax bills for every PIN for each TIF in the 27th ward.

Cory Mollet
TIF Report Project Lead Organizer

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