[GRASS-user] i.atcorr with wordview2 image return Nan values

Fabien Wagner wagner.h.fabien at gmail.com
Tue Apr 11 11:21:41 PDT 2017

Dear Grass users,

i am running i.atcorr on a worldview2 band (red band) and the resulting map
is empty, values are only NaN.

the input image is in reflectance, the values are integer between 0-255

i have set the g.region with the input image

the parameters are

16                                                  # indicates that it is
worldview2  image
12 11 15.750 -47.115 -22.822       # image taken on the 11th of December at
15:45 GMT in decimals; the center of the image lies at 47.115 °W  and
1                                                    # the tropical
atmospheric model
1                                                    # the continental
aerosol model
0                                                    # I have an estimate
of aerosol optical depth so 0
0.100                                             # aerosol optical depth
at 550nm
-.6121813                                      # the terrain lies 612
meters above sea level [km] * -1
 -770                                              # image taken of a
satellite sensor at 770 km
106                                                 # 106 : red band of the
worldview2 sensor

I see that the first part is ok,  the algorithm compute the estimated
visibility (63.66 km) , but then the atmospheric correction did not run and
produce and empty raster.

the test with an elevation raster didn't change nothing.
i have try to set by hand the wl inf and sup in the parameter file (wl
inf=    0.350 mic   wl sup=    1.100 mic,  for the red band ), here the
return by verbose is slighty different, but again i have an empty raster

does anyone have an idea of what i am missing ?


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