Australia’s Local Coordinates Are Out Of Sync With Global Ones, And Scientists Want To Correct That

Australia is on the move. The land down under is currently moving north by about 7 centimeters (2.75 inches) annually due to normal tectonic movements, and, as a result, the nation’s local coordinates are out of sync with those from the global navigation satellite systems (GNSS) by over 1.5 meters (4.9 feet) — which, incidentally, is the average height of a kangaroo.

In order to bridge this discrepancy, the Australian government has now launched a project to align the country’s coordinates with the GNSS. This would involve updating the Geocentric Datum of Australia — the country’s local coordinate system — that was last updated in 1994.

“We have points on Australia that are fixed to Australia and the lines of latitude and longitude move with those points,” Dan Jaksa from Geoscience Australia, the national agency for geoscience research and geospatial information, told ABC. “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.”

According to Jaksa, the new update, which will be published early next year, assumes special importance, given the advent of GPS-reliant technologies such as driverless cars and satellite farming.

“Around the corner, in the not too distant future, we are going to have possibly driverless cars or at least autonomous vehicles where, 1.5 meters, well, you’re in the middle of the road or you’re in another lane,” Jaksa said. “Quite frankly, we need to update the datum if they're going to become a reality.”

Australia is currently the fastest-moving continental tectonic plate in the world. That is why, the country’s local coordinate system had to be updated four times in the last 50 years in order to align it with global coordinates — which, since they are calculated based on global lines of latitudes and longitude, do not shift even when the continents do.

The new update will “overcorrect” the datum by about 20 centimeters (7.8 inches) as it would be based on projections of where the country would be in 2020.