In reply to:
Is there any way to give GRASS the proper scale of a scanned image, ie.
if a coast is 1.5km long and GRASS says it's 800m, how can you correct???- brian
If I understand you correctly, the problem seems to be that the real size
of the image pixels (1500 m) is not represented correctly in Grass, which
has cells measuring 800 m on a side. You can alter this fairly easily by
running the r.support, option 'change header', command. It will prompt you
for the correct region boundaries and cell size. Increasing cell size
from 800 to 1500 means that you have to change the boundaries too, of course.
Martijn van Leusen
SURF-image processing
Amsterdam