Geocentric Datum Of Australia 1994 (GDA94)

The Geocentric Datum of Australia (GDA94) is the official geodetic datum adopted nationally across Australia on 1 January 2000. GDA94 replaced the Australian Geodetic Datum 1966 (AGD66) and Australian Geodetic Datum 1984 (AGD84). The standard map projection associated with GDA94 is the Map Grid of Australia 1994 (MGA94), a transverse Mercator projection that conforms to the internationally accepted Universal Transverse Mercator Grid system.

GDA94 is a coordinate reference system that best fits the shape of the earth as a whole. It has an origin that coincides with the centre of mass of the earth, hence the term ‘geocentric’ GDA94 is a static coordinate datum based on the International Terrestrial Reference Frame 1992 (ITRF92), held at the reference epoch of 1 January 1994.

The GDA94 Gazettal values can be found in the GDA94 Technical Manual v2.4.