Geo rectifing photos

[Bart Cosyn]

This should be very easy to do. You only got to know how i.points or 
i.vpoints work. When you use i.points (after running i.group to get a 
list of the images to rectify and i.target to tell where the rectified 
image must be putted) a file POINTS is made in 
$GISDBASE/$LOCATION_NAME/$MAPSET/group/name_ofthegroup.
This file has an easy format (5 colums y:x:y_rectified:x_rectified:?)
In which column 5 contains 0(=exclude) or 1 (=include). In fact you can 
edit this file and enter the 3d and 4th column. 1 and 2 of the original 
image can be found using d.where!

To got more information try to run i.points on a test photo and check the 
format of the files! I refer to 

http://taoren.rug.ac.be/~bart/paper/node50.html

to get more info!

			Bart

	---------------------------------------------------	
	| ir. Bart Cosyn				  |
	| VLIR-project Tunisia				  |
	| Laboratory for Hydrology and Water Management	  |
	| University of Gent 			 	  |
	| Coupure 653, B-9000 Gent			  |	
        | Belgium 					  |
	| Tel: +/32/9/2646137				  |
	| Fax: +/32/9/2646236				  |	
	| E-mail: Bart.Cosyn at rug.ac.be   		  |
        | URL: http://taoren.rug.ac.be/			  |
	---------------------------------------------------

On Wed, 24 Jul 1996, G. Zacharioudakis wrote:

> Hello Grassusers
> We have some aerial photographs of an area.
> We do not know the coordinates of each photo to put it 
> in the location in GRASS but we know the coordinates of a few points 
> which are easily identified on the photos.
> How we can geo rectify the photos? (already converted to rasters) and 
> put them in the correct order to produde the whole area of interest??
> 
> Thank you in advance for your help
> 
> 
> 
> Giorgos Zacharioudakis
> School of Earth Sciences 
> University of Birmingham
> Edgbaston B15 2TT
> Birmingham
> UK
> Tel 0044 121 4146146
> Fax 0044 121 4143971
> e-mail:giorgos at ers.bham.ac.uk
>