News Item

Australia to move 5 ft

Australia is creating a new mapping datum to cope with both movement of its tectonic plate and the use of GNSS.

The Geocentric Datum of Australia 1994 (GDA94) - the existing national geodetic datum - is thought not to be capable of meeting the future requirements of users. Because the eastern part of the Indo-Australian tectonic plate is moving ~5.6 cm (~2.2 ins) per year, the data has become increasingly inaccurate over the past 2 decades.

Hence GDA94 will be modernised in a 2-staged approach to ensure that Australians continue to have access to the most accurate location-based information achievable. Two national spatial reference frames will be developed - first there will be a datum that is fixed to the Australian continent, where coordinates do not change with time; second there will be a reference frame that will allow locations of points and their movement over time to be modelled, accommodating coordinates that can change over time. Stage 1 implementation will commence on 1 January 2017, with Stage 2 nominally concluding 1 January 2023.

Stage 1 will deliver a new and more homogenous conventional plate-fixed (or static) datum, with defining coordinates projected forward to a reference date of 1 January 2020. The new datum will be known as GDA2020.

Stage 2 will see the Australian Terrestrial Reference Frame (ATRF) being implemented from January 2020 to 2023. The ATRF will be Earth-fixed and highly accurate with respect to the international ITRF and WGS84, used by GNSS - meaning that Australian spatial information and GNSS measurements will be directly interoperable.

All continents undergo tectonic movement and require conversion from local to international fixed datums such as WGS84, used by GPS. The UK's OSGB36 (1936) datum is well over 100m removed from WGS84 in many part of UK.

Details from the links below . .

Image from AEROmetrex Pty Ltd

  • 01 August 2016
  • RIN

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