Geographic Information System (GIS) Department


The new GIS Map Viewer is now available. Data requests may still be emailed to Josh Boudi.

GIS - What is it?

A Geographic Information System (GIS) is a computer-based tool for mapping and analyzing things that exist and events that happen on earth. GIS allows integration of all types of data based on the geographic component of the data. GIS technology combines common database operations such as query and statistical analysis with unique visualization and geographic analysis benefits. GIS is a powerful tool for governments and businesses to make informed decisions based on the "big picture" of related data. GIS is not an automated decision making system, but a tool to query, analyze, and map data in support of the decision making process.


Rock Island County began its GIS project in 1996 with the approval of the purchase of digital airphotos and a new digital soil survey. Digital conversion began in 1998 by digitizing "paper" mylar tax parcel maps in AutoCAD and editing with Environmental Systems Research Institute, Inc's (ESRIs) ArcInfo software. Digital orthophotography and property records are used to more accurately "adjust" data such as parcels and street centerlines.


The GIS Department is responsible for the development, maintenance, integration and training of GIS software applications and data layers for all County departments and agencies. Primary duties include:

  • Parcel Maintenance
  • Tax Parcel Maps Production
  • Internet Mapping Applications Development
  • High-end Data Analysis
  • Master Street Addressing Guide (MSAG) Maintenance
  • Development and Maintenance of Rock Island County's website
  • Quality Map Production

The GIS Department has also developed and now maintains accurate addressing data used by the five E911 dispatching centers in Rock Island County. The Computer-Aided Dispatching (CAD) system uses a street centerline and address point layer to indicate where the proper emergency services unit should be dispatched.

Available Data

Common data layers used by the GIS include:

  • Parcels - 65,000+ parcel boundaries
  • Streets - Street segments with address ranges
  • Soils - Soil types based on the most recent Natural Resources Conservation Service (NRCS) soil survey
  • Zoning - Zoning codes based on parcel boundaries
  • Census Data - Data provided by the U.S. Census Bureau
  • Taxing Districts - Boundaries of any taxing district in Rock Island County (i.e. schools)
  • Aerial Photography - Digital orthophotography beginning in 1995
  • (United States Geological Survey digital orthophotos (DOQs) are available for Rock Island County ranging from 1998 through 2000. These images can be downloaded from the Illinois Natural Resources Geospatial Data Clearinghouse.)

Commonly requested maps include parcel ownership, street centerlines, floodplain data, school districts, fire protection districts, voter precinct boundaries, traffic and crime statistics, zoning boundaries and parcel overlays with aerial photography.

Email Josh Boudi for all data requests or additional information and costs associated with available maps and data.

If you have problems downloading visit our Problems Downloading Page.