Maybe don't think of it as a map? Think of it as what you know. If you've never explored the world how do you know what's there? Pretty weak solution but hey, it works.
I hope to god they get through the 13th in tomorrow. The first wave go off at 5am my time and I've been waking myself up with the excitement of it all. I'm sooo tired. Luckily this thread has kept me occupied.