grs80 clarke1866 airy australianNational bessel clarke1880 everest fisher international modifiedAiry modifiedEverest walbeck wgs60 wgs66 wgs72 wgs84 clark58 krasovsky other
The reference ellipsiod is a method of approximating the shape of the geoid. The ellipsoid choice is typically implied by the horizontal adjustment system.
grs80: Refers to Geodetic Reference System 1980 (Moritz, 1980) which is a comprehensive coordinate system adopted by the Union of Geodesy and Geophysics. Used with nad83.
clarke1866: Refers to the non-geocentric reference ellipsoid used with nad27.
wgs60: Refers to World Geodetic System 1960.
wgs66: Refers to World Geodetic System 1966.
wgs72: Refers to World Geodetic System 1972.
wgs84: Refers to World Geodetic System 1984.
other: Allows for the specification of another reference ellipsoid.