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Illinois Height Modernization Program

Every engineering project, and many land-use planning efforts, require accurate measurements of heights. Correspondingly, a datum-consistent vertical and horizontal statewide network of survey benchmarks is needed, along with a statewide high-resolution digital elevation model (DEM) of the earth's surface. Unfortunately, Illinois currently falls far short of these goals and is ranked in the bottom ten states, regarding the quality of its elevation data. The National Geodetic Survey (NGS), part of the National Oceanic and Atmospheric Administration, provides funding to states through the federal Height Modernization program to improve the quality of elevation data using global positioning satellites (GPS) technology in conjunction with traditional leveling, gravity, and modern remote sensing. Illinois joined the NGS Height Modernization Program in 2008.


Survey within a road right of way.

ILHMP Project Milestones


All Project Years: 2008 to 2013

Year 1: September 2008 to August 2009

Year 2: September 2009 to August 2010

Year 3: September 2010 to August 2011

Year 4: July 2011 to June 2012

Year 5: July 2012 to June 2013

Year 6: July 2013 to June 2014