University of Wisconsin–Madison

Wisconsin Geospatial News

Information available on new geodetic datums to replace NAD 83 and NAVD 88 in 2022

As many of you already know, the National Geodetic Survey (NGS)–an office of the National Oceanic and Atmospheric Administration (NOAA)–is planning to replace the North American Datum of 1983 (NAD 83) and the North American Vertical Datum of 1988 (NAVD 88) with new datums in 2022.

horiz change

Approximate horizontal change in

coordinates when new reference 

frame is adopted.

Source: National Geodetic Survey

The new reference frame will:

  • be geo-centric
  • rely primarily on Global Navigation Satellite Systems (GNSS) such as the Global Positioning System (GPS)
  • rely on active control — Continuously Operating Reference Stations (CORS) — rather than passive control
  • incorporate a time-tracked geoid model with plate-fixed coordinates, to account for change in the x, y and z coordinates of points over time
  • adopt a US-specific reference frame with temporal coordinates using International Terrestrial Reference Frame (ITRF) coordinates and velocities
  • include a new vertical datum based on precise gravity measurements

The NGS hosted a Geospatial Summit in April 2015 to share updates and receive feedback on the planned 2022 release of the new datums.

The Presentations and webinar videos from the event are available through the NGS 2015 Geospatial Summit Website

The NGS website also contains useful information about the coming transition, including more videos and tutorials.

The replacement of NAD 83 and NAVD 88 is a significant undertaking requiring years of planning. The NGS website, videos, and tutorials provide a good starting point for getting introduced to some of the complexities of the process. Stay tuned for more information as this initiative takes shape over the next few years.