Global Positioning Shift

australia[Image: Australia, rendered by Neema Mostafavi for NASA].

Australia, it turns out, is not quite where maps think it is. Thanks to plate tectonics, the island nation is moving north by 1.5 centimeters a year, which means that the entire country is now nearly five feet further north than existing cartography suggests it should be.

As a result, Australia’s lat/long coordinates are going “to shift,” the BBC reports.

Interestingly, “the body responsible for the change said it would help the development of self-driving cars, which need accurate location data to navigate.” In other words, the navigational capabilities of autonomous vehicles and other self-driving robots are, at least indirectly, affected by plate tectonics—by the ground literally moving beneath their wheels.

“If the lines [of latitude and longitude] are fixed, you can put a mark in the ground, measure its co-ordinate, and it will be the same co-ordinate in 20 years,” explained Dan Jaksa of Geoscience Australia. “It’s the classical way of doing it.”
Because of the movement of the Earth’s tectonic plates, these local co-ordinates drift apart from the Earth’s global co-ordinates over time.
“If you want to start using driverless cars, accurate map information is fundamental,” said Mr Jaksa.
“We have tractors in Australia starting to go around farms without a driver, and if the information about the farm doesn’t line up with the co-ordinates coming out of the navigation system there will be problems.”

Put another way, gaps have been opening up between the world of robotic navigation and the actual, physical barriers those machines seek to navigate.

You could perhaps argue that there is our Australia—that is, a human Australia of streets, walls, and buildings—and then there is the machines’ Australia, a parallel yet intersecting world of skewed reference points and offset walls, a kind of ghost nation, inhabited only by robots, departing further and further from the limits of human geographic experience every day.

aussie
[Image: Via the Australian Intergovernmental Committee on Surveying and Mapping].

Of course, this would not be the first time that the accuracy of geographic information has a measurable effect on precision agriculture. However, it is also not the first time that geographers have realized that they don’t know precisely where a country really is.

In his recent book about GPS, Pinpoint, author Greg Milner writes about “the geopolitical importance of geodesy,” or the study of the Earth’s exact geometric shape (it is an “oblate spheroid”).

“The geopolitical significance of geodesy increased with the onset of the Cold War,” Milner writes. “In a very real sense, the West did not know the exact location of the USSR”—and, thus, did not know exactly how or where to target its missiles. “‘Missiles were the big drivers in getting the datums tied down,’ Gaylord Green remembers. ‘If I wanted to hit a target in Russia, I couldn’t hit squat if I didn’t have their datum tied down to mine.’”

Briefly, it’s worth pointing out a fascinating side-note from Milner’s book: “The trajectory a missile follows is influenced by the gravity field where it is launched, and its aim can be disrupted by the gravity at the target, so countries often kept their gravity data classified.” I love the John le Carré-like implications of classified gravity data, including what it might take to smuggle such info out of an enemy nation.

But let’s go back to the missile thing: in addition to the question of how farm equipment and other self-driving vehicles can successfully navigate the landscape when they don’t, in fact, have the correct terrestrial coordinates, Australia’s strange misplacement on global maps implies that every potential military target in the country would also have been roughly five feet away from where existing charts say they are.

An old, uncorrected missile system in a decaying military base somewhere mistakenly fires sixty years from now, rockets off toward Australia… and plummets into the sea, missing its coastal target by several feet. Plate tectonics as a slow national defense mechanism.

Read more at the BBC.

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