I guess our best bet is that the Academy and HQ facilities sprawl all over the current San Francisco area, and certainly include locations at both ends of the Golden Gate bridge.
The Tillman water reclamation plant grounds have been used for at least two distinct SF buildings: the Academy campus area in "First Duty", and the HQ in "Homefront". Only in the latter case was the plant decorated with additional matted-in elements... We might well deduce that the same architect designed a number of SF buildings on a variety of San Francisco locations, all of them looking more or less the same (and, incidentally, like the Tillman plant). It appears that the Academy campus is consistently show to the right of the north end of the bridge, while the location of the similar-looking HQ building is farther away from the bridge, far to the left of one or the other of its ends.
A massive structure was seen to the left of one of the bridge ends and apparently depicted HQ facilities in ST6. A similar structure was seen to the left of one bridge end in ST:TMP and again depicted the HQ. Funnily enough, those were shown as residing at different ends of the bridge! However, we might argue that both ends of the bridge look the same in the late 23rd century, for a brief while, until they are restored to looking different again in the 24th - the telltale difference is the fact evident from the above photos, namely that the north pylon is mounted ashore while the south pylon sits in the middle of the bay, on a caisson, with a stone arch between it and the shore. Given how often the bad guys target the landmark bridge, perhaps it was rebuilt a couple of times untrue to the original, and then restored.
http://movies.trekcore.com/gallery/albums/tuchd/tuchd0161.jpg
Other shots of the general area don't show this ST6 structure anywhere, whereas the TMP structure could easily exist nicely out of view in most shots. Perhaps this buildind was dismantled after ST6, or destroyed in yet another bad guy attack?
The general layout seems pretty consistent, though. Most of the HQ (including the broad views in DS9, VOY and ENT, but excluding the TMP facility) is in Sausalito; the Academy including its Tillman plant campus buildings is in Presidio, possibly with facilities on Treasure Island in STXI, or then on some sort of a massive barge floating in the bay (to allow for the two dissimilar views in the movie); and the fancy Tillman-adapted, Futurama-style HQ pavilion is somewhere relatively distant, either in the downtown/Marina area or then to the diagonally opposite banks of the north side of the inlet. The ST4 buildings including the landing pad appear to be somewhere between the Futurama pavilion and the bridge.
In any case, the area is much more heavily built in STXI than in other Trek. A simple timeline divergence, perhaps, with a different policy on urban planning.
Timo Saloniemi
Or maybe in the water?
It wont be offical, but at least its something.
