Advice wanted: rectifying of aerial photographs

[ENVSE]

>I need some expert advice on the (im)possibilities of rectifying
>aerial photographs with GRASS or other software. The problem: I
>received a set of hand-drawn maps that are based on a
 photo-interpretation
>of an area of approx. 10x15 km. The maps have been combined, by sticking
>colour copies together, to a map that is roughly on 1:20,000. However,
 the set
>of photos on which this map is based consists of two runs that are not
>exactly on the same scale. Needless to say that the number of reference
>points that I can find on the photographs is rather limited, and that
>the area is far from flat. The author of the map wants me to have it
>digitized and rectified in the UTM system.

Throw away the hand drawn stuck together stuff! It's useless for anything
other than wallpaper. 

>Is there any chance of doing this with a reasonable accuracy (e.g.
>with i.rectify), and if so, what are the conditions that should be 
>met? Any advice will be greatly appreciated!

You can do a reasonable rectification with the i. commands, but they
aren't great. You need as many points as you can find on a (preferably)
UTM reference map, (like a USGS 7.5 if you are in the US). Note, you
won't have any ortho rectification capability (correction for height)
w/ grass, so if you are in the rockies, forget about it.....if the image
is
in the netherlands on the other hand :). I can't remember  the exact
sequence
of i. commands...been 3 years since i did rectification in grass. I
believe it is i.group, then i.points, then i.rectify. Read the manual on
those three, and it will explain what to use first.

Marcus