This took so long and I swear I messed up somewhere. I think I know where my errors lie--although that's difficult to be sure of, considering how needlessly complicated the tutorial sometimes was.
It's a map of a land called Riven (after the verb, not the Myst sequel). It used to be one continent, but it was ripped apart by a storm. Much of it is entirely uninhabited, as it is only the second generation after the storm.
Random ideas do not leave me alone sometimes, but rarely do they come calling when I want them.