Well, i figured that since PiD was centered around an old mayan temple (which was in central america), i'd check around for an area which would look similar to it. It ain't france =p
Check out the Yucatan Peninsula (between mexico and Guatamala) at
http://plasma.nationalgeographic.com/mapmachine/
or some other map.
Orienting the map so that "Merida" is in the same area as Covenant would be, the maps seem to correlate fairly well. Even that island north of the twelve duns appears (along the n-e coast of peninsula)
Also, traveling far enough east on the myth map, (s,w on yucatan peninsula) you would find that you would eventually hit the ocean, but there would still be land masses to the north and south. Also, if a leveler or great hero came from either one of these two branches, he would arrive from the "west", and there are a significant number of small islands in the caribbean, the "east" from which small boats could easily come.
Let me know what you think, they look very similar to me.