Creating Legal Descriptions using GIS

The City of Des Plaines has a number of TIF Districts, as known as Tax Incremental Financing Districts.  A TIF is a method of public financing that is used to subsidize redevelopment, infrastructure and other city projects.  When a TIF is not functioning as it should it can become a hindrance to development within the district.  In these cases the TIF agreements and districts should be re-evaluated.


TIF 6 in Des Plaines is being redrawn and a new TIF District, TIF 7, is being created.  The TIF agreements need to have legal descriptions included with them to describe the land within the district.  GIS was able to assist the Community Development Department with drawing the legal descriptions and determining their accuracy.  

The legal descriptions that were created by the city staff, were drawn out in GIS using the calls, which consist of a northing, easting and distance such as, north 87 degrees 44 minutes 30 seconds east for 316.065 feet.  A legal description always begins with point of beginning and then a series of calls describe the boundary and eventually ends with a final call that brings the shape back to the point of beginning.  This allowed staff to see where there were potential errors in their original descriptions.  The GIS Department was then tasked with creating updated legal descriptions.  This was a relatively quick and easy process.  The COGO, coordinate geometry, toolset was utilized to determine the calls that were needed to create an initial accurate legal description, to be used for in house purposes.