Surveyor Information

What is a Ground Control Network?

ground control survey network is a framework of anchoring points for property boundaries. The monuments provide a reference tie to the Public Land Survey System (PLSS) to which all property records are referenced.

Why is this important?

Establishing the WinGIS Geodetic Ground Control Survey Network was an important project because it provides the framework and foundation for our digital base map system. Having a highly accurate network like the one established will improve maintenance efficiency, precision and accuracy of our base map resulting in future cost and time savings for WinGIS.

About the WinGIS Control Network

On June 22, 2000, Owen Ayres & Associates, Inc. entered into a professional services contract to provide a Geodetic Ground Control Survey Network for WinGIS. The contract included using a Global Positioning System (GPS) to locate and establish 128 pairs of monuments spaced approximately two miles apart throughout the county.

Each pair of monuments consists of one master station, a secondary master station (azimuth station) and a federal government section corner or other landbase monument. The azimuth station in conjunction with the master station allows for true bearing and azimuth determination. The federal government section corner or landbase monument provides a reference tie to the PLSS to which all property records are referenced.

The monuments are designed to meet the National Geodetic Survey (NGS) 3-D blue book monument standards. The monuments pairs are accessible by vehicle, meet the NGS minimum distance requirement of 2,000 feet or greater between pairs and are within the public right-of-way (ROW) for unrestricted access.

Additional Details About the WinGIS Control Network

The control network utilized the Wisconsin and Illinois High Accuracy Reference Network (HARN) station and NGS first order control station with vertical controls referenced to First and Second Order benchmarks by NGS and United States Cost and Geodetic Surveys.

The horizontal control network's relative position met or exceeded First Order (10mm +/- 10 ppm or 1:100,000) survey accuracy with Vertical Control meeting or exceeding Third Order (1:10,000) survey accuracy. The section corner or landbase reference positions met or exceeded Second Order, Class II (3.0cm +/- 50 ppm or 1:20,000) survey accuracy.