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The NAVD 88 project has dominated VNB activities since approval and funding in 1977. Major NAVD 88 tasks are described in detail in previous reports (Zilkoski 1986; Zilkoski and Young 1985). An important feature of the NAVD 88 program was the releveling of much of the first-order NGS vertical control network in the United States.
NAVD 88 was established in 1991. In 1993, Congress adopted NAVD 88 as the official civilian vertical datum for the United States and instructed all federal agencies to upgrade to the new datum. Since it was created, more than 450,000 benchmarks have been set with NAVD 88 elevations and there are more than one million kilometers of leveling data ...
The NAD 83 and the NAVD 88 datums also provide the necessary linkages for Global Positioning System (GPS) data and are supported by GPS continuously operating reference stations. Refer to the above information about including the datum realization date and epoch and geoid model information when using coordinates developed from GNSS surveys.
Mar 5, 2020 · North American Vertical Datum (NAVD) of 1988. The vertical control datum established for vertical control surveying in the Unites States of America based upon the General Adjustment of the North American Datum of 1988. It replaces the National Geodetic Vertical Datum (NGVD) of 1929. Last updated March 5, 2020.
NAVD 88 is a better realization of an orthometric datum based on a geopotential surface; however that geopotential is not the ideal global geoid. In addition, one will have average local departures from global mean sea level due to prevailing winds, currents, atmospheric pressure, temperature, and salinity effects.
NGVD 29 is the abbreviation for the National Geodetic Vertical Datum of 1929, the predecessor to NAVD 88. Due to the advancement of technology and surveying methods, the increased amount of available data and the level of accuracy of that data led to the new datum. The original datum used 26 tide stations throughout the United States and Canada ...
Conversion between NAVD 88 and the commonly used NGVD 29 varies spatially; however, over most of the study area the following conversion can be used: NGVD 29 = NAVD 88 –3.6 feet. This conversion generally is accurate within about ± 0.5 feet for 95 percent of the study area.
