no, although the map is square like FO3, the actual playing area is .. within that square. Like a strange long rectangle shape, with bits sticking out. ie it doesn't go right to the corners like FO3 did. (If you get/look at the game guide, it shows you the whole map, and its kind-of:)
---------------------------- ooooooooooo oooooooooooooooooo oooooooooooooooo ooooooooooooo ooooooooooooooo ooooooooooooooooo oooooooooooooo oooooooooo------------------------------
if that makes sense (sorry, it's a spoilerish thing)