Under a cooperative agreement with the National Geodetic Survey (NGS), we manage a statewide geodetic control data center that provides the Wisconsin geodetic community with federal geodetic control data, publications, and software. This section provides sources for control data, access to points including ControlFinder , transformation software, and handbooks.

In our clearinghouse role, we also provide advice and technical support to local units of government, state agencies, commercial firms, and the general public on procedures for accessing and reporting geodetic control data including the disturbance, removal, and recording of geodetic control markers in the state. To report a disturbed or destroyed control station, either fill out the Survey Station Condition Report, or submit the report by mail.

Accessing Geodetic Control (ControlFinder)
Our office maintains an online catalog called ControlFinder, which may be searched to retrieve information on geodetic control stations from federal, state, regional, and local sources.

ControlFinder features include:

•   a statewide view of control points
•   control from federal agencies (NGS & USGS)
•   control from selected counties
•   control representing the WI-HMP
•   access to online datasheets

Other Sources for Control Data

Wisconsin has well over 20,000 control points placed by numerous agencies over many decades, so the options for finding information on any one monument are varied.

The WI-DOT also has a large collection of geodetic control data resulting from highway construction, bridge projects, etc. The quality and availability of this information varies throughout the state. To determine what WI-DOT information may be available, contact the survey office in the appropriate WI-DOT district headquarters.

At the local level, county surveyors and county land information officers can often provide information about geodetic control for their areas. Other local sources of geodetic information may be utility companies, city engineers, and private surveying and engineering firms.

Other sources for control data include:
Wisconsin County Surveyors
Wisconsin Dept. of Transportation District Offices
Wisconsin County Land Information Offices
National Geodetic Survey
U.S. Army Corps of Engineers

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Transformation Software

WISCON, Version 2.2
Designed to transform coordinate values between geographic (lat/long), State Plane Coordinates (SPC), Universal Transverse Mercator (UTM), Wisconsin Transverse Mercator (WTM), and the new Wisconsin County Coordinate Systems. Datums supported include NAD27, NAD83(1986), NAD83(1991), NGUD29, and NAVD 88.

NADCON, Version 2.1
NADCON is the federal standard software for NSRS horizontal datum transformations. The program models a transformation of geographic coordinate (latitude and longitude) values between those based on the NAD 27 and NAD 83 datums.

CORPSCON, Version 5.x
Developed by the U.S. Army Corps of Engineers, CORPSCON is a combination of NADCON and other NGS software, and accommodates the transformation of data in several coordinate systems. CORPSCON does not currently support individual state high precision networks and therefore cannot resolve the transformation between more recent NAD 83 adjustments (i.e., CORPSCON will transform between the NAD 27 and NAD 83(86) datums only). However, NADCON and CORPSCON used in combination can be used to overcome this limitation.

VERTCON, Version 2.0
VERTCON is the federal standard for NSRS vertical datum transformations. It computes an approximate modeled difference in orthometric height between the NGVD 29 and NAVD 88 datums based upon a latitude and longitude location.

IGLD85
The IGLD85 (International Great Lakes Datum of 1985) is a datum transformation tool that converts NAVD 88 Helmert heights to IGLD85 dynamic heights and vice-versa. This computation can be done interactively, or in batch mode by submitting a file of data points.

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Handbooks

National Geodetic Survey Handbooks
We provide, for sale, five handbooks published by the National Geodetic Survey(NGS) as part of our cooperative agreement with the NGS in managing a statewide geodetic control data center for Wisconsin, Specific information about these handbooks can be found on our publications page.


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