I use this formula a lot when I'm doing external (or even internal!) programs/scripts that deal with Graal levels.
PHP Code:
base64 = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
temp.data = "aa";
temp.letters = {data.substring(0, 1), data.substring(1, 2)};
temp.tile = int((base64.pos(letters[0]) << 6) + base64.pos(letters[1]));
temp.tX = ((tile # 16) * 16) + (int(tile / 512) * 256);
temp.tY = tile # 512;
(Please replace # with a percent sign).