DuPage County is the second most populated county in the State of Illinois over 75% urbanized with a population now approaching 1,000,000. Starting in 1980 a G.I.S. program was initiated to make the county government entirely self-sufficient in meeting all mapping and G.I.S. data needs.

A first step toward this goal involved a program to re-monument the survey control section corners within the county. Prior to 1980 only a few of these monuments were permanent. Upon completion, this program reestablished and permanently installed survey control section corner monuments, as well as, numerous horizontal and vertical survey control monuments throughout the county. This new survey control information network provided the basis for the county's development of a G.I.S. digital mapping database.

The conversion from hand drawn quarter section maps to precision digitally input computer assisted map data was completed within 4 years. Each parcel or recorded sub-division of land in the digital map database was created by means of coordinate geometry using the bearing and distance information from recorded plats of survey. This produced a map database of sufficient accuracy for tax assessment purposes as well as future engineering work. Presently, ARC/INFO and ARCVIEW are the applications used to update the map database.

• Provides an accurate map database for all county departments.
• Tax Assessment
• Storm Water / Topological
• Zoning
• Land Use
• Election Redistricting
• Integration with Real Estate files to facilitate tax assessment.
• Provides an accurate base for new survey and engineering work.
• Used by many municipalities within the county for their mapping programs.