I bet those cartographers feel silly now. From BBC News:
A South Pacific island, shown on marine charts and world maps as well as on Google Earth and Google Maps, does not exist, Australian scientists say.The supposedly sizeable strip of land, named Sandy Island on Google maps, was positioned midway between Australia and French-governed New Caledonia.But when scientists from the University of Sydney went to the area, they found only the blue ocean of the Coral Sea.The phantom island has featured in publications for at least a decade.
You can read the rest of the story here. Apparently, incidents like this aren’t as uncommon as one might think: Wikipedia has a long list of other “phantom islands” that have been debunked throughout history. (My favorites from this list include Antillia, the mysterious Isle of Seven Cities, and the sinister-sounding Isle of Demons, a legendary land once believed to exist near Newfoundland.)