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1. • 

     VDatum

     • VDatum is a free software tool being developed jointly by NOAA's National Geodetic Survey (NGS), Office of Coast Survey (OCS), and Center for Operational Oceanographic Products and Services (CO-OPS).
     Reference:

     NOAA/NOS's VDatum 4.6.1: Vertical Datums Transformation

2. People also ask

   What is NAVD 88?

   • In 1993 NAVD 88 was affirmed as the official vertical datum in the National Spatial Reference System (NSRS) for the Conterminous United States and Alaska (see Federal Register Notice (FRN)). Although many papers on NAVD 88 exist, no single document serves as the official defining document for that datum.

   North American Vertical Datum of 1988 (NAVD 88)

   www.ngs.noaa.gov/datums/vertical/north-american-vertical-datum-1988.shtml

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   When will NAVD 88 be replaced?

   • NAVD 88, along with North American Datum of 1983 (NAD 83), is set to be replaced in 2025 with a new geometric reference frame and geopotential datum, based on GPS and gravimetric geoid models. Illustration of vertical datums in the United States.

   North American Vertical Datum of 1988 - Wikipedia

   en.wikipedia.org/wiki/North_American_Vertical_Datum_of_1988

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   Do flood maps need to be referred to NAVD 88?

   • As stated earlier, one goal of FEMA’s Risk Mapping, Assessment, and Planning (Risk MAP) program is to convert all flood maps from NGVD 29 to NAVD 88. Accordingly, FEMA Standard Identification Number (SID) 118 mandates that for areas within the continental United States, all new flood maps and updates must be referenced to NAVD 88.

   Guidance for Flood Risk Analysis and Mapping - FEMA.gov

   www.fema.gov/sites/default/files/documents/Vertical_Datum_Conversion_Guidance_Nov_2023.pdf

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   Are there any limitations to NAVD 88?

   • There are some limitations to NAVD 88 outside of the conterminous United States. NAVD 88 benchmarks are limited in Alaska. Many islands do not have any NAVD 88 benchmarks, have limited access to NAVD 88, or have other limitations with the geodetic control available.

   Guidance for Flood Risk Analysis and Mapping - FEMA.gov

   www.fema.gov/sites/default/files/documents/Vertical_Datum_Conversion_Guidance_Nov_2023.pdf

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3. www.vdatum.noaa.gov › vdatumwebOnline VDatum: Vertical Datums Transformation

   www.vdatum.noaa.gov › vdatumweb

   • Cached

   Datum Ellipsoidal Datum Orthometric Datum Tidal Datum. 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 ...

   • Vertical Datum

     The North American Vertical Datum of 1988 (NAVD 88) is the...

   • Datum Tutorial

     When dealing with paper maps and charts, the datums are...

   • Vertcon 3.0

     VERTCON 3.0 height shifts between NGVD 29 and NAVD 88....

4. www.asce.org › publications-and-news › civilGetting the height right: The North American Vertical Datum ...

   www.asce.org › publications-and-news › civil

   • Cached

   Nov 4, 2020 · HEIGHT DIFFERENCES BETWEEN NAVD 88 AND NGVD 29 IN CONTERMINOUS UNITED STATES; UNITS = CM (NOAA) According to the NGS website, surveyors used a method called Differential or Spirit Leveling, where a rod is held on a mark with a known elevation. “A reading is taken on the rod, which provides the elevation of the line-of-sight through the ...

5. en.wikipedia.org › wiki › North_American_VerticalNorth American Vertical Datum of 1988 - Wikipedia

   en.wikipedia.org › wiki › North_American_Vertical

   • Cached

   The definition of NAVD 88 uses the Helmert orthometric height, which calculates the location of the geoid (which approximates MSL) from modeled local gravity. [ citation needed ] The NAVD 88 model is based on then-available measurements, and remains fixed despite later improved geoid models.

6. www.fema.gov › sites › defaultGuidance for Flood Risk Analysis and Mapping - FEMA.gov

   www.fema.gov › sites › default

   the preference has been for new flood hazard studies to be referenced to NAVD 88. 1.3. Other Vertical Datums . There are some limitations to NAVD 88 outside of the conterminous United States. NAVD 88 benchmarks are limited in Alaska. Many islands do not have any NAVD 88 benchmarks, have limited