University of Wisconsin–Madison

Coordinate Reference Systems

Coordinate systems are used to accurately identify locations on the Earth’s surface, and are one of the fundamental building blocks that make modern Geographic Information Systems possible. Many of the links below refer to our 2009 publication, Wisconsin Coordinate Reference Systems. This 119-page publication is a revision of the Wisconsin Coordinate Systems handbook published by the SCO in 1995. The new handbook contains expanded information on coordinate reference systems commonly used in Wisconsin.

Coordinate Conversion & Transformation Tools

  • NGS Coordinate Conversion and Transformation Tool (NCAT) – Online tool for moving between State Plane, UTM, lat/lon, and USNG coordinates across several North American datums
  • WI-SDMS Translator – Desktop (Windows only) tool for converting between common coordinate systems used in Wisconsin. (Note: do NOT use SDMS for operations involving datum transformations.)
  • VERTCON – 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 –  A datum transformation tool that converts NAVD 88 Helmert heights to IGLD85 dynamic heights and vice-versa
  • PROJ 4: Cartographic Projections Library
Last updated: January 28, 2019