Regarding whether photographs can be brought into GRASS and 
registered: If the area you are working with is fairly flat, 
i.register might give satisfactory results. Otherwise, i.ortho can be 
used, along with a digital elevation model, to correct for terrain 
distortions in the photo. i.ortho does require standard aerial 
photography, however, including fiducial marks on the photo and a 
data on the characteristics of the camera.
Jim Schmidt
US Forest Service
Sonora, CA. 95370
(209) 532-3671


