clip & rectify

[JONATHAN DECKMYN]

Hi,

I want to rectify and clip a sattelite raster map to a dem.

The problem is the following :

I have a dem with a certain resolution (let's suppose 30m)
and a certain orientation.
I have an image with another resolution (let's suppose 100m)
and a certain different orientation (f.i. // instead of || )
This image also coverages a bigger surface then the dem.

Now I want to know how to get a new map from that image which the
same resolution and orientation as the dem.

So the problem is the following :
how grass takes care of these differences in resolution and orientation 
(which modules should I use and how do they work ---> the use of 
r.resample is not really clear to me , it says to use nearest neighbour to
do the resampling but when I look into r.neighbors the algorithm used for 
these kind of problems stays a mistery to me ..)

The final raster I want is a raster of the size and resolution of the dem with
the image-"derived" data (so I can export this raster also out of Grass)

Thanks in advance for every help.

        jonathan