[coordinate systems]
Acronym for North American Vertical Datum of 1988. The vertical control datum for heights used for surveying in the United States. NAVD is a leveling network on the North American continent with origin at Pointe-au-Père (Father Point), Rimouski, Quebec, Canada. It is referenced to the International Great Lakes Datum of 1985 mean sea level. NAVD 88 uses Helmert orthometric heights, which define the location of the geoid from leveling and gravity data.