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

[Markus Neteler]

On Mon, Oct 28, 2019 at 4:44 PM Moritz Lennert
<mlennert at club.worldonline.be> wrote:
> On 28/10/19 12:33, Markus Neteler wrote:
> > 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.
> >
>
> Sorry, wrong flag, should have been -l ("Linearly match histogram of
> Pan-sharpened output to Multi-Spectral input")

This comes with -l:

r.info -r wv2_17OCT08182034_M2AS_058891334010_01_P001.8.hpf
min=-932.700879728634
max=3456.94617091076

> And if you rescale the output manually to the input value range, do you
> still see a good fusion result ? If yes, then this could be added as a
> last step to the module.

In lack of time I cannot test that right now.

Nikos has a subset of my data, maybe he's able to check with that.

Markus