[GRASS-user] Orthorectification of Historic Aerial Photographs

[Maciej Sieczka]

Shaun & Melissa Busler pisze:
> Thank you so much for your response!  The resources you linked to were very
> useful.  The Erdas paper is especially good.  I never heard of MapAnalyst.
> I will have to give it a try.
> 
> Unfortunately, the focal length of the camera is not on the photo border.
> The photo must be too old.  Do you have any recommendations on what focal
> length I should try?

In one of the links already mentioned [1] there is a couple of hints. 
Maybe try asking on some RS-related ML?

> I was using photo2.image as part of the i.ortho.photo UI when I was having
> the problems.  It may be because I am using GIS-Knoppix.  If I use GIMP to
> measure the fiducial mark coordinates, do I still need to use photo2.image
> or do I just use photo.camera?

In GIMP measure fiducial marks coordinates, assuming you have the 
resolution of the image set right. In GIMP you can check it in Image > 
Print size - if the value there is wrong, set a correct one.

Then, in i.ortho.photo go through steps 1-3. In step 4 enter a name your 
camera parameters will be stored under. A dialog pops up for camera 
parameters. Once you enter the number of fiducial marks and press 
Esc+Enter, you will be prompted with a dialog for their coordinates - 
that's where to put values measured in GIMP.

Maciek

[1]http://www.pcigeomatics.com/services/support_center/faqs/oe_general_v10.html#no_fiducial