Main Office:
141 South Main Street, Suite 401
Decatur, IL 62523

Contacts:
Phone: (217) 424-1364
Fax: (217) 424-1374
email: gis@maconcounty.illinois.gov

Hours:
M-F 8:30 a.m. to 4:30 p.m.
excluding legal holidays

A geographic information system (GIS) is a computer-based system that is capable of storing, linking and analyzing data that are related by a geographic location. This system allows the users to visualize, question and analyze spatial data. Examples of spatial data include property boundaries, addresses, zoning districts, streets and roads, bike trails, precincts and election districts.

GIS is a tremendously powerful resource which leads to better decision making through improved communication, better record keeping, and higher efficiency.

Questions that GIS can help answer:

• Location: “Where is it?”
• Trends: “What has changed since…?…”
• Patterns: “What spatial patterns exist?”
• Modeling: “What if……”

Recently the County contracted with the Army Corp of Engineers to acquire Light Detection and Ranging (LIDAR) data for the entire county. This data will be used to create a Digital Elevation Model (DEM), a three dimensional model of the ground, that will be submitted to the Federal Emergency Management Agency (FEMA). FEMA will use this data along with other data collected in the field to update the County’s Digital Flood Insurance Rate Map (DFIRM). This map is used by insurers to determine if flood insurance is needed and is also used by the county for building and subdivision permits. This is not the only use for LIDAR data, the April issue of GEOWORLD magazine explains how LIDAR is being used for Natural-Resource and Agricultural Management.