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- The North American Vertical Datum of 1988 (NAVD 88) is the official vertical datum of the United States, having superseded the older National Geodetic Vertical Datum of 1929 (NGVD 29). Both NAVD 88 and NGVD 29 are geodetic datums, a reference surface of zero elevation to which heights are referred to over a large geographic extent.
www.mass.gov › info-details › north-american-vertical-datum-of-1988-navd-88
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Does NAVD 88 mean sea level?
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What is NAVD 88?
When was NAVD 88 renamed?
Nov 4, 2020 · The NAVD 88 used some of the original data from 1929 but also re-leveled about 100,000 km. Originally scheduled to be completed in 1988, it was finished on June 15, 1991. The new datum produced fewer distortions than earlier vertical datums and more accurate elevations, according to Remondi.
NAVD 88 was established in 1991 by the minimum-constraint adjustment of geodetic leveling observations in Canada, the United States, and Mexico. It held fixed the height of the primary tide gauge benchmark , referenced to the International Great Lakes Datum of 1985 local mean sea level (MSL) height value, at Rimouski , Quebec , Canada .
Jul 12, 2018 · Datum Information. Note: The Vertical Mark Number (VM) and Permanent IDentifier (PID) shown on the bench mark sheet are unique identifiers for bench marks in the CO-OPS and NGS databases, respectively. For bench marks where both VM and PID are indicated, both tidal and geodetic vertical datum elevations are available.
The product refers to an altitude or an elevation (orthometric height). State the vertical datum name and year in that document. Example: "Vertical coordinate information is referenced to the North American Vertical Datum of 1988 (NAVD 88)."
Jul 12, 2018 · What are NGVD 29 and NAVD 88? Why did NGS change from NGVD 29 to NAVD 88? What is the relationship between the geodetic vertical datums (NGVD 29 and/or NAVD 88) and the various water level/tidal datums? What is WGS 84? Does it change?
In contrast, the process for calculating NAVD 29 included only 106,724 (km) of leveling and 100,000 benchmarks. It’s important to note there is roughly a one-foot difference between the two datums, depending on the location in the country.
Topographic maps (from USGS, for example) will have elevations referenced to either NAVD 88 or the older NGVD 29. Except for the largest map scales, the horizontal components of WGS 84 and NAD 83 may be considered equivalent. Even if the features are horizontally referenced to NAD 83, this does not mean the vertical datum is a 3-D vertical datum.
