The Australian continent tectonic plate is moving 7 cm a year (and colliding with the Pacific Plate, which is heading west 11 cm a year) and experts at Geoscience Australia are trying to keep up.
Australia’s maps are currently based on a national spatial reference system called the Geocentric Datum of Australia 1994 (GAD94), which is more than 20 years old and ties map references to locations fixed on the Australian continent.
A team of scientists is about to recalculate the nation’s latitude and longitude coordinates, which are currently out by more than 1.5 metres. It will improve the accuracy of all spatial information across the nation for a myriad of services including transportation, personal navigation and surveying.
According to reports by Australian Broadcasting Corporation, Dan Jaksa from Geoscience Australia said:
The renewal was essential because there was a growing gap between the current positions and the coordinates used by Global Navigation Satellite Systems, such as GPS.
“We have points on Australia that are fixed to Australia and the lines of latitude and longitude move with those points,” he said.
“The lines are fixed to the continent but as time goes by, that position compared to a GPS position can create a difference, so every so often we need to change that.”
The new datum (GDA 2020) will be published early next year but will be based on projections to 2020, which means in 2017 the data will be out by about 20cm but that gap will slowly close each year.
To read more about questions related to datum transfer fro GDA94 to GDA 2020 refer survey report of Intergovernmental Committee on Surveying and Mapping (ICSM).
The survey responses indicated there is a good level of base knowledge about the modernisation of GDA94 and the move to GDA2020 but indicated that still more needed to be done, within and without the spatial sector, to raise awareness of the change and details of the process proposed.