explain how to test

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@37105 15284696-431f-4ddb-bdfa-cd5b030d7da7

imagery/i.atcorr/test_suite/README.txt

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+Test suite i.atcorr
+
+ETM4_atmospheric_input.txt = File with the atmospheric and sensor conditions
+ETM4.res                   = Output file showing the atmospheric and sensor conditions
+ETM4_400x400.raw           = Image input file
+ETM4_400x400_atms_corr.raw = Image output file (expected output)
+
+
+# try in Spearfish location or other:
+
+# import raw Landsat channel 4:
+r.in.gdal ETM4_400x400.raw out=ETM4_400x400.raw -o
+# set region to this map
+g.region rast=ETM4_400x400.raw
+
+# run atmospheric correction on imported channel 4:
+i.atcorr -r --o iimg=ETM4_400x400.raw \
+         icnd=./ETM4_atmospheric_input_GRASS.txt \
+         ialt=dem \
+         oimg=ETM4_400x400.corrected
+
+# import already corrected test data set for comparison:
+r.in.gdal ETM4_400x400_atms_corr.raw out=ETM4_400x400_atms_corr -o
+
+# compare:
+r.mapcalc "diff = ETM4_400x400_atms_corr - ETM4_400x400.corrected"
+r.colors diff color=differences
+
+r.univar diff
+