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    • Geoid Height and Deflections of the Vertical Models

    Metadata Updated: July 24, 2025

    In Gauss' words, the geoid is "the mathematical figure of the Earth". This figure is an equipotential surface coincident with the idealized mean sea surface. The geoid can be computed from the geodetic boundary value problems that use gravity data as its boundary value. A geoid model computed using gravity data is called a gravimetric geoid. On the other hand, geoid height at bench marks can also be computed using data from spirit leveling and the Global Positioning System (GPS). A geoid model that is fixed to the GPS/leveling data is called a hybrid geoid. Both geoid models can serve as the zero-height-surface of a country's height system by selection. To satisfy this need, National Geodetic Survey has published a series of geoid models (https://geodesy.noaa.gov/GEOID).

    The vast majority of navigation and positioning applications utilize a hybrid geoid model with the latest model being GEOID18 for CONUS and Puerto Rico/U.S. Virgin Islands and GEOID12B for all other states and territories of the United States. The corresponding gravimetric geoid for these regions is xGEOID19B and USGG2012, respectively. All models are provided at 1 arc-minute resolution.

    Access & Use Information

    License: No license information was provided. If this work was prepared by an officer or employee of the United States government as part of that person's official duties it is considered a U.S. Government Work.

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    Dates

    Metadata Date July 15, 2025
    Metadata Created Date July 24, 2025
    Metadata Updated Date July 24, 2025
    Reference Date(s) 1996 (creation), 2019 (revision), 2013 (publication)
    Frequency Of Update notPlanned

    Metadata Source

    Harvested from NOS NGS

    Other Data Resources

    Additional Metadata

    Resource Type Model
    Metadata Date July 15, 2025
    Metadata Created Date July 24, 2025
    Metadata Updated Date July 24, 2025
    Reference Date(s) 1996 (creation), 2019 (revision), 2013 (publication)
    Responsible Party (Point of Contact, Custodian)
    Contact Email
    Guid gov.noaa.nmfs.inport:39739
    Access Constraints Cite As: National Geodetic Survey, [Date of Access]: Geoid Height and Deflections of the Vertical Models [Data Date Range], https://www.fisheries.noaa.gov/inport/item/39739., Access Constraints: None, Use Constraints: Data in the NGS Integrated Database (IDB) are constantly updated, hence older hybrid geoid models are not consistent with newer ellipsoid and orthometric heights present in the IDB today. To obtain the most consistency between GPS derived ellipsoid heights and NAVD 88, the latest hybrid geoid model valid for that region should be used, either GEOID18 or GEOID12B. While the hybrid geoid model(s) extends into Canada, Mexico, Bermuda, the Bahamas, and into large water bodies like the Great Lakes and ocean, these model(s) have no real value in those places and should not be used in those areas. The reason for this is that significant extrapolation errors can be present and expected in areas where there are no GPS on bench mark data to constrain the model., Distribution Liability: Data in the NGS Integrated Database (IDB) are constantly updated, hence older hybrid geoid models are not consistent with newer ellipsoid and orthometric heights present in the IDB today. To obtain the most consistency between GPS derived ellipsoid heights and NAVD 88, the latest hybrid geoid model valid for that region should be used, either GEOID18 or GEOID12B. While the hybrid geoid model(s) extends into Canada, Mexico, Bermuda, the Bahamas, and into large water bodies like the Great Lakes and ocean, these model(s) have no real value in those places and should not be used in those areas. The reason for this is that significant extrapolation errors can be present and expected in areas where there are no GPS on bench mark data to constrain the model.
    Bbox East Long -60
    Bbox North Lat 58
    Bbox South Lat 24
    Bbox West Long -130
    Coupled Resource
    Frequency Of Update notPlanned
    Harvest Object Id 8221a495-e6af-400d-9cd4-ad828fd95541
    Harvest Source Id ea6e63e6-96bb-4fb1-a72f-b7af08062c83
    Harvest Source Title NOS NGS
    Licence NOAA provides no warranty, nor accepts any liability occurring from any incomplete, incorrect, or misleading data, or from any incorrect, incomplete, or misleading use of the data. It is the responsibility of the user to determine whether or not the data is suitable for the intended purpose.
    Lineage
    Metadata Language eng
    Metadata Type geospatial
    Old Spatial {"type": "Polygon", "coordinates": [[[-130.0, 24.0], [-60.0, 24.0], [-60.0, 58.0], [-130.0, 58.0], [-130.0, 24.0]]]}
    Progress completed
    Spatial Data Service Type
    Spatial Reference System EPSG::4269
    Spatial Harvester True

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