Hi all,<br><br>I want to do an atmospheric correction of my Landsat ETM+ images using the i.atcorr module in Grass 6.3 on Ubuntu, but I never get an output. When I use a DEM in <i>ialt</i>, the continuous version or the categorized, of the region, I just get "wavelength less than 0.25 micron let's take s(1)=s(0.25)". I don't insert an altitude value in my <i>icdn</i> file however, since I've read that that value would overwrite the DEM. When I do put in an altitude value, I get a list with the parameters for the 6S-algorithm, and then 'percent complete', so that seems to be ok, but the algorithm stops running, so I don't get a corrected image. Does anyone have experience with this module, and help me with some tips, preferably so I can use my DEM instead of one altitude value for the whole image?<br>
<br>This is my <i>icdn </i>file when I use the DEM:<br>8<br>2 12 08.500 +35.2203028 -2.8893705<br>1<br>0<br>-1<br>-1000<br>64<br><br>and this when I use one altitude for the whole region:<br>8<br>
2 12 08.500 +35.2203028 -2.8893705<br>
1<br>
0<br>
-1<br>1000<br>
-1000<br>
64<br><br><br>Thanks in advance!<br><br>Kind regards,<br>Annekatrien<br>