NOAA Center for Operational Oceanographic Products and Services, NOAA National Geodetic Survey, NOAA Office of Coast Survey


Converts elevation data between tidal, orthometric, and ellipsoidal vertical datums, allowing users to establish a common reference system for all elevation data sets. The conversion tool is based on a hydrodynamic model to convert between tidal and orthometric datums.


  • Transform geospatial data between a variety of vertical datums (i.e., tidal, ellipsoidal, and orthometric datums)
  • Convert between datums using several geoid models
  • Convert between the International Great Lakes Datum (IGLD) of 1985 and NAVD88.

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