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NAVD 88 –3.6 feet
- NGVD 29 = NAVD 88 –3.6 feet. This conversion generally is accurate within about ± 0.5 feet for 95 percent of the study area.
pubs.usgs.gov › sir › 2010
The grids in VERTCON 3.0 release 20190601 are replacements for those in VERTCON 2.1, which transformed only between NGVD 29 and NAVD 88 for CONUS. However VERTCON is no longer the name of a stand-alone transformation tool.
May 21, 2024 · For coordinate conversion, NCAT allows conversion between lat/long/height, SPC, UTM, XYZ, and USNG systems. NCAT currently uses NADCON* to perform three-dimensional (latitude, longitude, ellipsoid height) coordinate transformations and VERTCON* to perform orthometric height transformations.
Web VDatum is designed to vertically transform geospatial data among a variety of tidal, orthometric and ellipsoidal vertical datums - allowing users to convert their data from different horizontal/vertical references into a common system and enabling the fusion of diverse geospatial data in desired reference levels.
Jul 12, 2018 · The datum is defined by the observed heights of mean sea level at the 26 tide gauges and by the set of elevations of all bench marks resulting from the adjustment. A total of 106,724 kilometers of leveling was involved, constituting 246 closed circuits and 25 circuits at sea level.
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.
Originally known as Sea Level Datum of 1929, NGVD 29 was determined and published by the United States Coast and Geodetic Survey [2] and used to measure the elevation of a point above and depression below mean sea level (MSL).
NGVD 1929 Conversion to NAVD 1988. Community officials and the NFIP use the newer, more accurate elevation datum to consistently assess risk for buildings and to complete flood insurance ratings. NAVD 1988 is the newer elevation datum. An easy way to convert BFE data is through the National Geodetic Survey (NGS) online tool known as VERTCON.
