For those who asked --

Photogrammetry is a process by which photographs are scanned in to the
computer.  In the old days (say, 1990) perspective rectified photographs would
have to be taken with a 4x5 camera, scanned in to something like Photoshop,
then reduced or enlarged to some scale.  These photos could then be used as
base elevation drawings -- rather than completing measured drawings.

Now the photogrammetry programs actually will scale the photos, or video tape
for you if you give it base points with key dimensions.  The promo materials
leads you to believe that the computer does it all.  I don't believe it.  Soon
we won't need Architects!

Still looking for information.
Anne Sullivan