Prairie Research Institute

Illinois State Geological Survey

Height Modernization

The Illinois Height Modernization Program is a part of a federal initiative for state and regional partners. The program aims to enable access to accurate, reliable, and consistent heights nationwide. Elevation information contributes to informed decision-making and impacts a wide range of important activities, including mapping and charting, flood risk determination, transportation, land use, and ecosystem management.

Lidar data

ISGS provides essential high-resolution digital elevation data for every Illinois county; these data are used for planning by local, state, and federal agencies. Height modernization and elevation data are available at

Data are collected using airborne light detection and ranging (lidar) remote sensing technologies. Products derived from lidar data have proven to be efficient and accurate tools for mapping river forecasts used in flood emergency response for public safety; implementing flood control; floodplain mapping and regulation; risk analysis; delineating building footprints; identifying geological landforms and archaeological features; planning for dam removal; conducting levee and watershed analyses; and evaluating habitats, including tree canopies and individual tree counts and heights. 

By comparing lidar data collections from different years, it is possible to discern many land-use changes over time.