Using an aerial view, is there a formula to determine the pitch of the roof

[JustinFeckted]

so I'm trying to find an equation that will tell me the angle of the camera. I.E. if I have a flat piece of paper on a table and I'm looking at it from a certain angle. Is there a way to determine the angle at witch I'm looking at it by measuring the seemingly altered angles of the paper. given that the corners of said paper are all known to be 90 degrees. and furthermore, if the shape in question was pitched. would I be able to determine the pitch? the best example I can think of is. perhaps the oblique angle of a simple house. using a single aerial view.

TL;DR.... Using an aerial view, is there a formula to determine the pitch of the roof?

 

[tkhunny]

You must have some useful reference.

Distance to object.
Measurements of Object.
Exact measurement of some nearby object?
Distance to nearby object?

Something. You can't just take a photo and hope.

 

[JustinFeckted]

We figured it out, without any additional references.

Thanks anyway.