I thought it looked like a map too. Seeing the pic here, it's definitely the case, since it says (I am here) at the bottom. The symbol on the station at the upper left looks like a medical symbol, so that's probably where Claire, Danielle, and Kate went a few weeks back. Remember that when Jack, Locke & Sayid all explored the hatch at the beginning of the season, they found certain hallways were walled off. This might be the Xed out hallway. Perhaps all the stations have a tunnel leading to the center of the island, but they've all been sealed. Too bad we can't read any of the writing. Anybody with Tivo and HDTV have any better luck?
I'd be willing to bet that the blast doors dropped in relation to the resupply plane, but why? To keep the subjects inside in the dark about the resupply plane? A plane that no one out side on the island heard? Maybe there is no plane... that's why the hatch-dwellers aren't allowed out side?
And with "Henry" definitely an Other (no surprise there), I have to wonder if he even entered the code at all.
Good ep.