Reference Ellipsoid

In geodesy, a reference ellipsoid is a mathematically-defined surface that approximates the geoid, the truer figure of the Earth, or other planetary body. Because of their relative simplicity, reference ellipsoids are used as a preferred surface on which geodetic network computations are performed and point coordinates such as latitude, longitude, and elevation are defined.

Read more about Reference Ellipsoid:  Ellipsoid Parameters, Coordinates, Historical Earth Ellipsoids, Ellipsoids For Other Planetary Bodies

Famous quotes containing the word reference:

    I am more and more convinced that, with reference to any public question, it is more important to know what the country thinks of it than what the city thinks. The city does not think much.
    Henry David Thoreau (1817–1862)