<div dir="ltr">
















<p class="MsoNormal" style="text-align:justify"><span lang="EN-GB" style="font-family:Calibri">Dear all,</span></p>

<p class="MsoNormal" style="text-align:justify"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal" style="text-align:justify"><span lang="EN-GB" style="font-family:Calibri">I am recent GRASS GIS user who is trying to
run the <i>i.atcorr</i> module to
atmospherically correct a Landsat ETM+ image in GRASS 7 (on MacBook Pro,
Mavericks OSX). This image has been already converted to reflectance with <i>i.landsat. toar</i>. I also use a DEM file
obtained from ASTER GDEM. All these files are projected to UTM zone 36 S. </span></p>

<p class="MsoNormal"><span lang="EN-GB"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">I have followed the steps described
in the manual and everything seems to be fine except that the process returns
an empty raster (all raster values equal to NoData).</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> This is the command:</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">i.atcorr –r –a input=
LakeChirwaN-REFL1@Malawi parameters=/Users/Xavi/Desktop/LCDM.txt
output=LakeChirwaN_REFL1_ATCORR</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">And the LCDM file looks like
this:</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">8          
                                     --
Landsat ETM+</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">5 26 7.487 </span><span lang="EN-US" style="font-family:Calibri">35.753 -14.414  -- </span><span lang="EN-US" style="font-family:Calibri;color:rgb(38,38,38)">month
day hh.ddd longitude latitude</span><span lang="EN-US" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">1                                               -- Atmospheric model: tropical</span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">0                                               -- Visibility</span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">-0.009                                      
-- Aerosol Optical Depth 550 nm</span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">-0.650                                      
</span><span lang="EN-US" style="font-family:Calibri">-- Mean target elevation (in Km) *-1</span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">-1000                                       
-- Sensor height (on board a satellite)</span></p>

<p class="MsoNormal"><span lang="EN-US" style="font-family:Calibri">61                                            -- Sensor band (ETM+ band 1)</span></p>

<p class="MsoNormal"><br></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">Could someone give help me on
this please?</span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri"> </span></p>

<p class="MsoNormal"><span lang="EN-GB" style="font-family:Calibri">Thanks in advance!!</span></p>

</div>