GEOID18 will be the last hybrid geoid model that NGS will create before NAVD 88 is replaced by the North American-Pacific Geopotential Datum of 2022 (NAPGD2022). Hybrid geoid models convert NAD 83 ellipsoid heights to NAVD 88 orthometric heights by constraining a gravimetric geoid to published heights at bench marks. Specifically, GEOID18 is intended for use with coordinates in the NAD 83 (2011) reference frame. NGS will replace GEOID12B with GEOID18 in early 2019. GEOID18 only covers CONUS, Puerto Rico, and the US Virgin Islands. Users in Alaska, Hawaii, Guam, American Samoa, and CNMI should continue to use GEOID12B.
Updated on August 14, 2019