Over the next few years, users of Australian spatial datasets will have the opportunity to transition from using coordinates referenced to the Geocentric Datum of Australia 1994 (GDA94) to the Geocentric Datum of Australia 2020 (GDA2020). The technical information that covers the use of both national datums can be found on this page.

The technical information provided here:

  • defines GDA94 and GDA2020;
  • provides descriptions, transformation parameters and examples to assist with datum transformations between GDA94, GDA2020, realisations of the International Terrestrial Reference Frame (ITRF) and historic Australian datums;
  • provides descriptions and examples to assist with coordinate conversions between Earth-centred Cartesian, geographic and map projected coordinates;
  • provides descriptions and examples of coordinate computations; and
  • defines the Australian Height Datum (AHD) and AUSGeoid models, and describes how to convert between ellipsoidal heights and Australian Height Datum heights.


   Download the GDA2020 Technical Manual v1.8 (PDF – 3 MB)




   Download the GDA94 Technical Manual (PDF - 2.18 MB)

   Download the GDA94 Technical Manual (Word - 3.74 MB)





    TECH Fact sheet 1: GDA94 to GDA2020 transformation




Feedback and comments can be emailed to geodesy@ga.gov.au.