[GRASS-dev] i.fusion.hpf addon: observing strong range change

[Nikos Alexandris]

* Nikos Alexandris <nik at nikosalexandris.net> [2019-10-28 17:14:54 +0100]:

>* Markus Neteler <neteler at osgeo.org> [2019-10-28 12:33:44 +0100]:
>
>>On Mon, Oct 28, 2019 at 10:46 AM Moritz Lennert
>><mlennert at club.worldonline.be> wrote:
>>>On 27/10/19 18:52, Markus Neteler wrote:
>>>> Hi,
>>>>
>>>> I am using i.fusion.hpf on Worldview-2 data and see that the resulting
>>>> range is completely different:
>>>>
>>>> # orig
>>>> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.5
>>>> min=0
>>>> max=1509
>>>>
>>>> # HPF
>>>> r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.5.hpf
>>>> min=-1045.79783524995
>>>> max=3416.06793724612
>>>
>>>Just guessing here, but did you try the -c flag ?
>>
>>Now yes:
>>
>>i.fusion.hpf pan=$PAN msx=$(g.list raster pattern="$COLORPREFIX.?"
>>sep=comma) -c --o
>>
>># band 8
>>r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.8
>>min=0
>>max=1605
>>
>>r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.8.hpf
>>min=-1163.98434592277
>>max=3879.99538075697
>>
>>So, -c doesn't seem to have any effect here.
>
>Mean values (and StdDev) don't change too much though. As I am looking
>over the algorithm again, these days, I'll try to answer this in the
>best possible way.
>
>Cheers, Nikos

Also, try the histograms too.  Shapes are rather preserved.  Scales are
not.

Here some images:
https://send.firefox.com/download/87f58d62ece20cb4/#6YJsCoKi7yW5wUiMbcs1LQ
(link expires after 5 downloads or 7 days).

Nikos

-- 
Nikos Alexandris | Remote Sensing & Geomatics
GPG Key Fingerprint 6F9D4506F3CA28380974D31A9053534B693C4FB3