Mystery island on 1908 map
The mystery of a disappearing island in the South Pacific may have been solved by a curious librarian at Auckland Museum.
Until this week, Sandy Island was believed to sit between Australia and New Caledonia in the South Pacific, plotted on Google Earth, marine charts and world maps.
But when a team of Australian scientists sailed past the island's supposed location on a recent research trip, the island was nowhere to be seen.
"We became suspicious when the navigation charts used by the ship showed a depth of 1400 metres in an area where our scientific maps and Google Earth showed the existence of a large island," said Dr Maria Seton, a geologist from the University of Sydney.
"Somehow this error has propagated through to the world coastline database from which a lot of maps are made."
The missing island has regularly appeared in scientific publications since at least 2000.
"Even onboard the ship, the weather maps the captain had, showed an island in this location," Dr Seton said.
Neither the French Government - the invisible island would sit within French territorial waters if it existed - nor the ship's nautical charts, which are based on depth measurements, had the island marked on their maps.
Intrigued by the mystery, Auckland Museum's pictorial librarian Shaun Higgins went looking through the museum's vast collection of maps, which dates back as far as the 1700s.
Eventually, Higgins found a 1908 map which showed the island, which appears to be about the size of Great Barrier in the Hauraki Gulf.
According to the map the island was discovered by the ship the Velocity in 1876 - but on the map was a caveat that warned the information may not be reliable, as it was gathered over a number of trips.
A note on the map reads: "Caution is necessary while navigating among the low-lying islands of the Pacific Ocean. The general details have been collated from the voyages of various navigators extending over a long series of years. The relative position of many dangers may therefore not be exactly given."
Higgins said how the island managed to appear, disappear and reappear on various maps and charts over time was "a mystery of the sea".
"No doubt some out there will believe the island is still there, or has simply moved south for the summer," he wrote in a blog post about his research.
The "un-discovery" of Sandy Island took place onboard the RV Southern Surveyor, Australia's Marine National Facility research vessel, during a 25-day research trip in the eastern Coral Sea.