Oz- using the continents, European is 'D', American is 'A', Hispanic is 'b'?, and Asian is a really fugly 'T'.
Also, the arpeggio spells something, what I don't know. I see a y, a sideways G, an o, a j,, a E and a A, a T, a m i, the OZ, naturally, a r and a few islands over a ir. Perhaps someone smarter can put those together, I'm just doing my part to help.
A great map, Oz. I appreciate your hard work.