CMAP periodically conducts a survey of the region's land use, publishing the results in GIS format as the Land Use Inventory. The inventory is an essential input to CMAP's land use and transportation research. Other users of the data include county planning departments, regional transportation agencies, federal & state agencies, university researchers, non-governmental organizations, environmental consulting firms and civil engineering firms.
Beginning with the 2010 Inventory, land use polygons are now derived directly from parcel GIS files provided by the seven counties in the CMAP region. Switching to a parcel base allows for greater accuracy as well as faster turnaround times for updates.
Previous inventories (1990 through 2005) were "polygon-based," meaning land uses were carried out to street centerlines, ignoring rights-of-way (ROWs) except for very large roadways. Using a parcel base, land uses no longer extend beyond property boundaries. The graphic below illustrates the difference between the two versions:
A commercial strip on Chicago's South Side. Left: aerial photograph. Center: "polygon-based" land use from 2005. Right: "parcel-based" 2010 land use; dark grey represents road and alley rights-of-way.
A result of working with parcel boundaries is that some land use categories from the 2005 and earlier inventories were retired or modified. For example: the "Wetland" and "Vacant Forested/Grassland" categories are no longer in use because they rarely conform to property boundaries.
Road ROW and many water bodies are not represented by parcels; to fill in these gaps, CMAP created a series of "non-parcel" polygons representing these un-parceled areas. Users of these data are urged to read the accompanying metadata and additional supporting documentation to understand the inventory's structure.
The 2013 Land Use Inventory and 2010 v.2
The 2013 Land Use Inventory is now available on the CMAP Data Hub. It is considered an update of the 2010 product and focuses on areas where changes in Assessor records or parcel geometry between the two years was detected. Its formatting and classification scheme are identical to the 2010 Inventory.
Additionally, an updated 2010 Inventory (version 2) is available. This version applies corrections to errors uncovered while working on the 2013 Inventory.
Downloading CMAP Land Use Data
GIS files and documentation for the 2013 and earlier inventories can be found here.
Production on the 2015 Inventory begins in 2017, with completion anticipated in late 2018.