Finally got all of the canisters. Took me 3 run throughs with a map and a pen. What I ended up doing was checking every building next to the one marked (espically if they we higher up) to get a better perspective of possible locations of the canister.
Wish I would have thought of it my first time through though.
Thanks to Gackt for the awesome sig!
Please msg me on XBL first for boosting, I don't accept random friend requests