Abstract

Update and refinement of the North American Datum of 1983
Track: Surveying
Authors: Michael Dennis

The North American Datum of 1983 (NAD 83) is the official geometric ('horizontal') datum of the US and the basis for navigation, surveying, and mapping, including GIS. The National Geodetic Survey (NGS) recently updated and refined this datum with a new realization referred to as NAD 83(2011) epoch 2010.00 (the epoch indicates a January 1, 2010 date for the positions, important in tectonically active areas like California). The realization was achieved through processing, adjustment, and analysis of GPS-derived data for approximately 80,000 survey control stations. It yielded new highly accurate coordinates for these stations and represents a significant step toward more integrated NGS products and services. This presentation will show how NGS used GIS technology for analysis and display of results. It will also provide users with guidance on implementing NAD 83(2011) epoch 2010.00 for their spatial data, including transformation to previous realizations of NAD 83 (e.g., HARN and NSRS2007/CORS96).