Australia is on the move.

The continent drifts in a north-north-east direction at rate of 7cm a year. But, from this year, its recorded latitude and longitude will move 1.8 metres – a scheduled update to the local coordinate system to reflect the movement of the Earth’s tectonic plates.

The transition to the new datum, overseen by Geoscience Australia, will be gradual over the next two years. But for the 10,000 or so Australians who use coordinates for geocaching, it has sparked much discussion.

Geocaching began in the early 2000s as a sort of real-world treasure hunt, or high-tech orienteering, in which players hunt for registered “caches” hidden and recorded by other players.

The cache itself is a box, often a reusable food container, though the only requirement is that it is watertight and large enough to hold a logbook. A player hides it and records its location with enough detail for it to be found by another player, who will then take something out of the box and replace it with an item of equal or greater value.

James Finger, a forensic scientist and president of Geocaching NSW, says it combines “bushwalking and geeky technology”.

“The old axiom is ‘Geocachers: We use multi-billion dollar satellite technology to hunt for boxes in the bush. What’s your hobby?’”

Since 2009, he has made about 5,800 finds, which he says puts him “at about the middle of anyone who’s taking it seriously”. He managed just over 400 this year, but backpacking through Europe “in a previous life”, he racked up a streak of more than 1,000 days.

With between six and eight million players (and 2.8 million caches) registered around the world, the game has grown as the technology has become more accessible. In 2000, a top-of-the-line, over-the-counter GPS unit could take a player to within 20m of the hidden cache, Finger says.

“But now your new smartphones have got comparable accuracy – if you know how to use them – with a basic bushwalkers’ unit. That’s what’s spurred the popularity. You no longer have to buy a dedicated piece of kit, you can do it on your smartphone.”

Though the change of Australia’s latitude and longitude has “sparked some conversation amongst the community”, he says it will have little impact on geocachers, who use the global World Geodetic System – not the Australian datum.

When GPS systems on most web-enabled smartphones, such as Apple maps or Google maps, take you to between 10-20m from the cache – “so a 1.8m shift is not really significant” anyway.

Finding a cache also depends on the accuracy of the coordinates recorded by the person who hid it – which could be as much as 30m out from its true location, depending on factors such as nearby buildings or power lines that might have compounded the reading.

“When the numbers on your screen say you’re about 10m away, you generally put this thing away in your pocket, and you start looking around, and you rely on your own experience and intuition,” Finger says.

The game has changed in the best part of two decades, he says: with most players introduced to geocaching through their smartphones, its links to orienteering skills and geographic systems have become more nebulous.

Discussion of the technology involved – even of latitude and longitude – is more interesting for “the old guard”.

“Your modern generation of geocachers may not know there is such a thing as a dedicated GPS handheld device,” he says. “It’s like trying to explain to your kids the days when mobile phones did not have the internet.”

Most geocachers simply interact with the game at face value, as they would Pokémon Go, to which it’s often compared. (“Except it’s been around 15 years. It’s as old as the original Pokémon games are, in fact.”)



Finger predicts that games and interests incorporating GPS technology will only increase. “It’s basically a free thing for the public and game developers to utilise, and it’s one the average person is now familiar with and comfortable with.

“Nearly everyone who owns a smartphone will use Google maps: they know what it is, they know vaguely what it can do for them. Turning that into a hobby or interest is not as massive a step as it was to those first bushwalkers who were told to trust instructions to find a hidden box.”