[GRASS-user] Re: i.atcorr returns all NULL values

Gaspar Reyes Póndigo gos47 at hotmail.com
Fri May 27 16:46:36 EDT 2011 

I had same problem, i.atcorr not work with landsat 5TM band 1, 2 and sometimes with band 3
I tried i.atcorr in different versions of grass, this is my results:

1. GRASS-6.4.1-2 under Mac Snow-Leopard 10.6.7: Not work band 1, 2, and sometimes with band 3 (for years 1992, 1993, 1995 and 1997).
2. GRASS-6.5. revision 46428 compiled in Mac Snow-Leopard 10.6.7: Not work band 1, 2, and sometimes with band 3 (for years 1992, 1993, 1995 and 1997)
3. GRASS-6.5svn45719(2011) under Microsoft Windows Xp sp3: All the bands work,THIS IS VERY RARE 

My images landsat 5 TM are from Tonameca, Oaxaca, México of years 1985 to 1999, and 2010 to 2011 (one image series for year), i am work with AOD and visibility value,  and convert manually DN to radiance (a).

(a) Lλ = [(LMAXλ − LMINλ) / (Qcalmax − Qcalmin)] (Qcal − Qcalmin) + LMINλ 

Gaspar Reyes Póndigo
Universidad del Mar, Oaxaca, México
Campus Puerto-Ángel
Carretera principal Puerto Ángel Zipolite km 1.5 
C.P. 70902

> -------------------------------------------------------------------
> 
> Message: 1
> Date: Fri, 27 May 2011 08:53:32 +0530
> From: "Chemin, Yann (IWMI)" <Y.Chemin en cgiar.org>
> Subject: RE: [GRASS-user] Re: i.atcorr returns all NULL values
> To: "Juan Benavides Duque" <jbenavid en siu.edu>,
> 	<grass-user en lists.osgeo.org>
> Cc: Markus Metz <markus.metz.giswork en googlemail.com>,	Elena Mezzini
> 	<elena.mezzini en gmail.com>
> Message-ID:
> 	<001F233294EA894387CFDAADAB87DE25085063E9 en iwmix.IWMI.CGIARAD.ORG>
> Content-Type: text/plain; charset="us-ascii"
> 
> Hi Juan,
> 
> 
> 
> Can you please give the download link for your images,
> 
> Could you also check the output of i.landsat.toar for them and tell if
> reflectance ranges are valid/logic.
> 
> 
> 
> Thank you,
> 
> Yann
> 
> 
> 
> From: Juan Benavides Duque [mailto:jbenavid en siu.edu] 
> Sent: Thursday, May 26, 2011 11:38 PM
> To: Chemin, Yann (IWMI)
> Cc: Markus Metz; Elena Mezzini
> Subject: Re: [GRASS-user] Re: i.atcorr returns all NULL values
> 
> 
> 
> 
> I tried Yann's code for the i.atcorr on some Landsat TM5 images
> 
> It worked very nice for images taken after 1995 but before that still
> returns null values when running i.atcorr for bands 1 and 2 
> 
> I used TM5 scenes from the same location for 1986, 1989, and 1996 and
> the first two (1986 and 1989) had the same problem with the null
> values... 
> 
> sorry I can provide a way to fix it but  I hope somebody will
> 
> juan c 
> 
> 
> 
> 
> 
> 
> On Tue, May 24, 2011 at 3:49 AM, Chemin, Yann (IWMI)
> <Y.Chemin en cgiar.org> wrote:
> 
>> Each created visibility map holds only one value r.mapcalc
> expression="visibility=${vis_list[$i]}" --overwrite so why not just use
> this visibility value as input in the >parameter file instead of
> creating a map where all cells have the same value?
> 
> Yes, this is a valid point, the script is designed to (hopefully soon)
> encompass raster maps of visibility data (maybe interpolated...), so
> this is a placeholder for the next steps.
> 
> 
> -----Original Message-----
> From: Markus Metz [mailto:markus.metz.giswork en googlemail.com]
> Sent: Tuesday, May 24, 2011 12:52 PM
> To: Chemin, Yann (IWMI)
> Cc: grass-user en lists.osgeo.org; Elena Mezzini; Markus Neteler
> 
> Subject: Re: [GRASS-user] Re: i.atcorr returns all NULL values
> 
> On Mon, May 23, 2011 at 9:36 PM, Markus Neteler <neteler en osgeo.org>
> wrote:
>> Hi Yann,
>> 
>> On Mon, May 23, 2011 at 5:07 AM, Chemin, Yann (IWMI)
> <Y.Chemin en cgiar.org> wrote:
>>> p192 r030 image of July 2003 of Italy (L5TM) successfully corrected
>>> for band 1 and 2.
>>> The following script works well in GRASS GIS Trunk SVN.
>> 
>> (better send as attachment since a series of line breaks got broken)
>> 
>> ...
>>> # For i.atcorr scripting
>>> #-----------------------------------------------------
>>> vis_list=(10 10 8 9.7 15 8 7 10 10 9.7 12 9.7 7 12 12 12 3 15 12 9.7
>>> 6 15) vis_len=${#vis_list[*]} echo $vis_len
>> 
>> ... this is not clear to me: why so many values and where do they
>> originate from? Since we have only 6 channels to work with...
>> 
> Moreover, how can it be possible that visibility is different for
> different channels of the same scene? From the documentation it seems
> that visibility is related to aerosol concentration at 550nm which can
> not possibility be different for different bands of the same scene.
> Each created visibility map holds only one value r.mapcalc
> expression="visibility=${vis_list[$i]}" --overwrite so why not just use
> this visibility value as input in the parameter file instead of creating
> a map where all cells have the same value?
> 
> Markus M
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> 
> 
> 
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