(NGVD) is a geodetic datum derived from a general adjustment of the first order level nets of both the United States and Canada. It was formerly called "Sea Level Datum of 1929" or "mean sea level". Although the datum was derived from the average sea level over a period of many years at 26 tide stations along the Atlantic, Gulf of Mexico, and Pacific Coasts, it does not necessarily represent local mean sea level at any particular place.
The datum established in 1929 by the U.S. Coast and Geodetic Survey as the surface against which elevation data in the United States is referenced.
Reference surface established by the U.S. Coast and Geodetic Survey in 1929 as the datum to which relief features and elevation data are referenced in the conterminous United States; formerly called "mean sea level 1929."
The average of the heights of the sea surface at all stages of tide. In photogrammetry, the National Geodetic Vertical Datum of 1929 is also referred to as Mean Sea Level.
An information standard for measuring an area's elevation. It established a specific sea level by taking observations at 21 tide stations and then used this point for determining elevations in reference to that point for locations in the U.S. and Canada.
A geodetic reference for elevations, completed and adjusted in 1929. These elevations were used to define the mean sea level datum. This datum was replaced by NAVD 88.
Datum established in 1929 and used in the NFIP as a basis for measuring flood, ground, and structural elevations, previously referred to as Sea Level Datum or Mean Sea Level. The Base Flood Elevations shown on most of the Flood Insurance Rate Maps issued by the Federal Emergency Management Agency are referenced to NGVD.