I'm a little disappointed that this article makes such a big claim but actually states in the last map that all land is discovered. First of all I don't think it's true. At least some spots will be visited so infrequently or only by a disconnected tribe of people that it's basically unexplored. And second the whole discussion doesn't make sense if all land is discovered. Of course there are undiscovered pieces of water (maybe including small islands) somewhere. For lack of importance they don't count though.