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Mar 9, 2024 · Geodesists use a horizontal datum as the model to translate a spheroid/ellipsoid into locations on Earth with latitude and longitude lines. Geodetic datums form the basis of coordinates of all horizontal positions on Earth. We reference all coordinates on Earth to a horizontal datum.
May 21, 2023 · For instance, in geometry, we use x (horizontal) and y (vertical) coordinates to define points on a two-dimensional plane. The coordinate system used to define locations on the three-dimensional earth is the geographic coordinate system (GCS), based on a sphere or spheroid.
A horizontal datum is used to measure a location across the Earth's surface, in latitude and longitude or another coordinate system; a vertical datum is used to measure the elevation or depth relative to a standard origin, such as mean sea level (MSL).
Dec 7, 2023 · National Geodetic Survey Datums, Frames and Projections information covering vertical datums, horizontal and geometric datums, new datums, datum transformations, coordinate conversions and tidal datums
Horizontal Datum: The North American Datum of 1983 (NAD83) Vertical Datum: Typically the North American Vertical Datum of 1988 (NAVD88), although the National Geodetic Vertical Datum of 1929 (NGVD29) and local reference datums are used in some areas outside of the conterminous United States.
Datums are one component of a geographic coordinate system (GCS). A GCS includes a datum, angular unit of measure, and a prime meridian. Datums are often thought of as geographic coordinate systems because it is very rare that the units are not degrees (versus grads) and often utilize the same prime meridians.
