[GRASS-user] Orthorectification of Historic Aerial Photographs

[Maciej Sieczka]

Shaun & Melissa Busler pisze:

> 1) When is i.ortho.photo going to be available for the Windows binaries?

Dunno. It currently depend on X displays, not easily portable to else 
than Unix.

> 2) The historic aerial photos do not have camera calibration files.  I have
> searched all over and they do not seem to exist anymore.  Is there a way to
> orthorectify the images without the camera calibration files?  Can I make
> some assumptions?  If so, what parameters should I enter?

If the DPI at which photos have been scanned is known to you, you can 
measure the principal point and fiducial marks coordinates in any image 
editing software, like GIMP. Interior orientation results will depend on 
  how close is the geometry of the image plane to the geometry of 
camera's optical system, and if/how the photo scan is distorted.

Idea, not tested: you might try using software like MapAnalyst [1] to 
asses the distortion of the image, which can help you guessing genuine 
fiducial marks coordinates.

Then you need the focal length. It often is present on the photo border. 
Or guess it :).

> 3) When I tried using photo.2image, I was not prompted with "Look ok?
> (Y/N)"  so I was not able to mark the fiducials.

photo.2image is not supposed to be used standalone. i.ortho.photo is the 
UI for photo.2image & friends.

There's plenty of info you might find usefull on the net. eg. [2] [3].

[1]http://mapanalyst.cartography.ch
[2]http://support.erdas.com/focus3/files/Aerial_photo.pdf
[3]http://www.pcigeomatics.com/services/support_center/faqs/oe_general_v10.html#no_fiducial