This seems to be a sort of anti-blank: Google and others put something on the map that wasn't actually there, and which contradicted the existing oceanographic charts.
I know the sort of thing you mean, though: the Ordnance Survey (the UK national mapping organisation) routinely had blank spaces on its maps where there were actually important military sites until the 1990s. One of them has a railway line ending in the middle of nowhere, where in fact there's a complex network.