Go to the helicopter pad and look for a yellow beam you can jump on, then follow it and then jump on the next yellow beam.

Then there should be a small building you jump on and then go on the other side of it and jump on the next yellow beam and it should lead you to a big long bridge.

Get onto the bridge and go all the way left and look at the thing that slants up, kind of high.

Face the railing and press A and turn 90 degrees and walk up the beam. Stay up on the top for a great view of the map.