Practical and Technical Considerations for the Replacement of NAD 83

English Abstract:

The official U.S. horizontal mapping datum, the North American Datum of 1983 (NAD 83)—in both its definition, as well as the services NGS provides for its access—is in need of improvement. As defined, it is non-geocentric by over two meters and has non-zero, residual plate velocities. Since 1983, increasingly accurate International Terrestrial Reference Frames (ITRF) have become available and have been adopted by many groups, including Mexico's INEGI and the U.S. National Geospatial-Intelligence Agency.

The U.S. National Geodetic Survey is planning a replacement of NAD 83 with a new ITRF-aligned geometric datum, to be released with a new GNSS-accessible geopotential datum to replace the North American Vertical Datum of 1988. We will discuss recent progress, expected benefits, planned products, services, models, and tools to access the new datum, legislative steps, and impacts and concerns from Federal, State, Private Sectors.