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

Nikos Alexandris nik at nikosalexandris.net
Wed Apr 12 03:58:12 PDT 2017


* Fabien Wagner <wagner.h.fabien at gmail.com> [2017-04-11 15:21:41 -0300]:

>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
>-22.822°S
>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 ?

Dear Fabien,

this https://trac.osgeo.org/grass/ticket/2059 is still standing, as far
as I can tell.

Nikos


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