[GRASS-user] unexpected i.pansharpen results

[Markus Metz]

On Thu, Jan 31, 2013 at 7:06 PM, Michael Barton <Michael.Barton at asu.edu> wrote:
>
> i.pansharpen uses Python, not Bash. So it is not an integer math problem.

But it calls r.mapcalc, e.g. in lines 151-153. If k is integer and not
float, r.mapcalc will do integer division. Equivalent for lines 159,
162, 165. This could be fixed by casting the numerator to double with
double().

Markus M

>
> However, you might try changing your input maps to float or DCELL. See if that changes things.
>
> Michael
> ______________________________
> C. Michael Barton
> Director, Center for Social Dynamics & Complexity
> Professor of Anthropology, School of Human Evolution & Social Change
> Arizona State University
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>
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>
> On Jan 31, 2013, at 2:11 AM, <grass-user-request at lists.osgeo.org>
>  wrote:
>
> From: Yann Chemin <yann.chemin at gmail.com>
> Subject: Re: [GRASS-user] unexpected i.pansharpen results
> Date: January 31, 2013 2:11:33 AM MST
> To: Hamish <hamish_b at yahoo.com>
> Cc: GRASS user list <grass-user at lists.osgeo.org>
>
>
> hmmm, yes that looks like an old friend to check...
>
>
> On 31 January 2013 14:06, Hamish <hamish_b at yahoo.com> wrote:
>>
>> (sorry for the html,top posting)
>>
>> I wonder if the script is doing integer division when it should be doing floating point division?
>>
>> http://trac.osgeo.org/grass/browser/grass/trunk/scripts/i.pansharpen/i.pansharpen.py
>>
>>
>> Hamish
>>
>> --- On Wed, 1/30/13, Eric Goddard <egoddard1010 at gmail.com> wrote:
>>
>>
>> From: Eric Goddard <egoddard1010 at gmail.com>
>> Subject: [GRASS-user] unexpected i.pansharpen results
>> To: grass-user at lists.osgeo.org
>> Date: Wednesday, January 30, 2013, 8:30 AM
>>
>>
>> Hi all,
>>
>> I'm attempting to pansharpen some ikonos imagery using the i.pansharpen tool in Grass7 on windows 7 installed via OSGeo4W (r54756-478).  The range for the sharpened red, green, and blue outputs are 0-30, which seems suspicious given the 16bit range of the input bands. The command I used was:
>>
>> i.pansharpen.py "sharpen=ihs" "ms3=ik_mss.4 at eric" "ms2=ik_mss.3 at eric" "ms1=ik_mss.2 at eric" "pan=ik_pan at eric" "output_prefix=ik_ihs"
>>
>> The input bands are linked via r.external, would that matter?
>>
>> The output from my test area is below. Any assistance would be greatly appreciated.<image.png>
>>
>>
>> Thanks,
>> Eric
>>
>> -----Inline Attachment Follows-----
>>
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