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Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Data Products

Published by NOAA National Centers for Environmental Information | National Oceanic and Atmospheric Administration, Department of Commerce | Metadata Last Checked: December 18, 2025 | Last Modified: 2017-09-01T00:00:00.000+00:00
Within the NOAA National Ocean Service (NOS), the NOAA National Geodetic Survey (NGS) has a federal mandate to provide accurate positioning, including heights, to all federal non-military mapping activities in the USA. In 2007, the NGS embarked on the Gravity for the Redefinition of the American Vertical Datum (GRAV-D) Project, one of the most ambitious projects in the history of the agency. The gravity-based vertical datum resulting from this project is accurate at the 2 cm level where possible for much of the country. Available data include airborne and terrestrial survey information, gravity data, and gravity-based geoids or datums.

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