Hi Mike,

For my research, I really wanted to calculate the proportion of building 
frontages which were glazed (to test the oft-mentioned proposition that 
"Dutch" buildings have "big" windows).

This is very easy to calculate from architectural drawings or rectified 
photography, but as you note, photographers in the past - and today - 
are not taking photographs for us to calculate from!  So they are fouled 
up (from our point of view) by perspective.

The only reference I came across which was at all relevant was Crankshaw 
Ned     1990    'CARPA: Computer Aided Reverse Perspective Analysis.' 
APT Bulletin: The Journal of Preservation Technology    XXII, no. 1&2
However, this does not _quite_ do what I wanted.

So I found a friend who happens to be a Cambridge mathematician, and he 
and his friends (and, I suspect, some beer) had a look at the problem, 
and they could not find a solution (this doesn't mean there isn't one, 
of course).

I also tried to solve this practically, by taking an oblique photograph 
of a building for which I had a measured drawing.  I then 'stretched' 
the photograph so that lines were brought back to horizontals, but found 
that without knowing the height of the point of view (along with the 
broad dimensions of the building), it was not possible to do this 
accurately.

With best wishes to all,

Pat

In message <[log in to unmask]>, HISTARCH 
automatic digest system <[log in to unmask]> writes
>I am presently attempting to determine building dimensions and the
>distances between structures from historic photographs taken during the
>1880s and 1890s.  I've been using various photogrametric calculations and=
>
>perspective drawing measuring techniques, but I can't help but feel that =
>I
>may have overlooked something.  As such, I would appreciate it if someone=
>
>could provide me with information / references for determining dimensions=
>
>from historic photographs.

-- 
Pat Reynolds