[GRASSLIST:5057] Re: difficulties with i.ortho.photo

Markus Neteler neteler at itc.it
Mon Nov 25 06:27:32 EST 2002

On Sun, Nov 24, 2002 at 01:06:30PM +0300, Guillaume Criloux wrote:
> Hello,
> I am using i.ortho.photo to ortho-rectify aerial images of Mayotte (Comoros Archipelago).
> The associated man pages are not very clear about a few points.
> When i register a camera, what is this "point of symmetry" that i have to locate on the photo ? What is the origin and direction of X and Y on the photo ?
> When i must enter fiducial and reseau marks, where is the origin ? is it the same as the point of symmetry that i talked about above or is the point of symmetry the new origin ?
> Well, if someone has experience in using i.ortho.photo and explain me a bit, i'd be very grateful.

Please have a look at

I have added some explanations. Please suggest if this is not sufficient.

Best regards 
 Markus Neteler

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