[GRASS-user] i.atcorr returns empty Raster in GRASS 7

Markus Neteler neteler at osgeo.org
Tue Jan 7 12:56:13 PST 2014


On Mon, Jan 6, 2014 at 11:11 PM, Xavier de Lamo <xavi.delamo at gmail.com> wrote:
> Dear all,
>
> I am recent GRASS GIS user who is trying to run the i.atcorr 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.landsat. toar.

Could you please post here the range values of the first four
channels? Something like
r.info -r channelX
(or use the GUI)

Just to be sure that the i.landsat. toar output is right.

> I also use a DEM file obtained from ASTER GDEM. All these
> files are projected to UTM zone 36 S.
> 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).
>
>  This is the command:

Please also post the i.landsat.toar command here.


> i.atcorr –r –a input= LakeChirwaN-REFL1 at Malawi
> parameters=/Users/Xavi/Desktop/LCDM.txt output=LakeChirwaN_REFL1_ATCORR
>
> And the LCDM file looks like this:
>
>
>
> 8                                               -- Landsat ETM+
> 5 26 7.487 35.753 -14.414  -- month day hh.ddd longitude latitude

Is the order of longitude and latitude right?
The hh.ddd is in correct GMT?

> 1                                               -- Atmospheric model: tropical
> 0                                               -- Visibility

Zero visibility mean full darkness? :-)

> -0.009                                      -- Aerosol Optical Depth 550 nm
> -0.650                                      -- Mean target elevation (in Km) *-1
> -1000                                       -- Sensor height (on board a satellite)
>
> 61                                            -- Sensor band (ETM+ band 1)
>
> Could someone give help me on this please?

Please doublecheck the parameters in the control file.

Markus


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