How to combine a set of adjacent raster maps

[Grass package]

"JAY" writes:

[lines deleted]
> 
> Database"  supported by USACERL. But we have a problem :
> 
>      We have a set of low altitude aerial photographs, which are translated
> 
> to raster map files by  scanner  and  "r.in.tiff" (a command).
> 
>      How can I combine (or say match) a set of adjacent photographs (raster
> 
> map) in GRASS ?????  (Is there some existent GRASS tools or functions can do 
> 
> this work ?   of course, this work must include some rectification jobs.)
> 
>      My e-mail address : jay at flower.amath.nchu.edu.tw
>      1995/1/19  jay in TAIWAN
> 
By using the georeferencing/rectification tools i.source, i.target, i.points
and i.rectify2 you can put each photograph into its correct geographic
position. If you then display all four on the screen they will be visually
matched. If you want them patched together into one file, use r.patch. To
facilitate georeferencing, I always scan in and georeference a topographic
map of the area first, then use point and click methods to reference the 
photos to the map. Hope this helps...

Martijn van Leusen