Re: [Qgis-developer] Feedback for contrast enhancement ... enhancements ?

[Andrew]

One note I would add is that the  2-click option does not work with a
singleband pseudocolor renderer(neither does the raster toolbar which
offers a 1-click stretch).  So I think updating the right-click>"Stretch
using current extent" to work with singleband pseudocolor would be
excellent to include. Also, I agree that min/max would be good as a
default, for singleband at least.  Beyond that I like the sound of solution
and I would love to see this functionality in QGIS.

a

On Fri, Sep 2, 2016 at 3:38 AM, Even Rouault 
wrote:

> Hi,
>
> There has been interest expressed to improve the usability of the contrast
> enhancement function. Basically there are workflows where you want the
> min/max
> values used by contrast enhancement to be updated each time you pan or zoom
> the canvas. From what I've seen, here's what currently exists:
> - a long method (6 clicks): through the Style tab of the layer properties
> - a faster method (2 clicks): through the "Strech using current extent" of
> the
> contextual menu of the layer panel.
>
> When you have several rasters loaded, even the 2-click method is
> inconvenient,
> so there's a need for a 0-click solution (once the layers have been
> configured)
>
> Another shortcoming in the current implementation is that the settings of
> the
> "Load min/max values" foldable group are not persistant, which requires re-
> setting them if you're not happy with the default Cumlative count cut
> method.
> And if you use the "Strech using current extent" menu item, the genuine
> min/max values are used (not the 2-98% cumulative count cut)
>
> So I was thinking to something along the following lines:
> - make the min/max settings persistant
> - remove the "Load" button and "Clip extent to canvas" checkbox, and
> replace
> them by 3 radio buttons to determine the scope of statistics : "Whole
> raster",
> "Current canvas" and "Updated canvas". See the attached
> proposal_min_max.png.
> The function of the Load button would be replaced by the general Apply / OK
> buttons.
> - when the user manually enters the min/max values, the 2 groups of radio
> buttons (method to compute min/max and scope of statistics) would be
> unchecked
> so that is is clear that they don't come from computed statistics. I also
> think that when you select "Current canvas", once the Apply/OK buttons have
> been pushed, the checked state of Current canvas shouldn't be saved. This
> way
> when you display the layer properties you have a good idea of where the
> current min/max values come from.
> - make the "Strech using current extent" method honour the way min/max are
> computed in the min/max settings instead of using systematically the
> min/max.
> So when "Updated canvas" would be selected, it would have no (extra)
> effect as
> expected.
>
> Any opinions ?
>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>
> ___
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Re: [Qgis-developer] Feedback for contrast enhancement ... enhancements ?

[Mathieu Pellerin]

Please don't change the default behavior for 3-band rasters to min/max;
while it does make in many scenarios for 1-band rasters (DEM, precipitation
value, vegetation index, etc.), this is a terrible default value for most -
if not all - satellite imagery products (i.e. Sentinel-2, LANDSAT-{5,7,8},
ASTER, etc.).

IMO, we need to have two separate default option: one for 3-band raster
min/max (which doesn't change), and one for 1-band raster (which is changed
to min/max).



On Fri, Sep 2, 2016 at 7:00 PM, Nyall Dawson  wrote:

> On 2 September 2016 at 21:50, G. Allegri  wrote:
> > +1
> >
> > I would also make min/max the default option, because I've has many users
> > (mostly newcomers) were struggling too find out why some pixels were not
> > displaying as expected. It was because the statistics weren't including
> > some, few, important pixels.
>
> Yes please! There's so many users on stackexchange who get confused
> with this same issue.
>
> Nyall
>
> > Anyway I know that, generally, cutting the tails provide a better visual
> > result.
> >
> > giovanni
> >
> >
> > Il 02/set/2016 12:39, "Even Rouault"  ha
> > scritto:
> >>
> >> Hi,
> >>
> >> There has been interest expressed to improve the usability of the
> contrast
> >> enhancement function. Basically there are workflows where you want the
> >> min/max
> >> values used by contrast enhancement to be updated each time you pan or
> >> zoom
> >> the canvas. From what I've seen, here's what currently exists:
> >> - a long method (6 clicks): through the Style tab of the layer
> properties
> >> - a faster method (2 clicks): through the "Strech using current extent"
> of
> >> the
> >> contextual menu of the layer panel.
> >>
> >> When you have several rasters loaded, even the 2-click method is
> >> inconvenient,
> >> so there's a need for a 0-click solution (once the layers have been
> >> configured)
> >>
> >> Another shortcoming in the current implementation is that the settings
> of
> >> the
> >> "Load min/max values" foldable group are not persistant, which requires
> >> re-
> >> setting them if you're not happy with the default Cumlative count cut
> >> method.
> >> And if you use the "Strech using current extent" menu item, the genuine
> >> min/max values are used (not the 2-98% cumulative count cut)
> >>
> >> So I was thinking to something along the following lines:
> >> - make the min/max settings persistant
> >> - remove the "Load" button and "Clip extent to canvas" checkbox, and
> >> replace
> >> them by 3 radio buttons to determine the scope of statistics : "Whole
> >> raster",
> >> "Current canvas" and "Updated canvas". See the attached
> >> proposal_min_max.png.
> >> The function of the Load button would be replaced by the general Apply /
> >> OK
> >> buttons.
> >> - when the user manually enters the min/max values, the 2 groups of
> radio
> >> buttons (method to compute min/max and scope of statistics) would be
> >> unchecked
> >> so that is is clear that they don't come from computed statistics. I
> also
> >> think that when you select "Current canvas", once the Apply/OK buttons
> >> have
> >> been pushed, the checked state of Current canvas shouldn't be saved.
> This
> >> way
> >> when you display the layer properties you have a good idea of where the
> >> current min/max values come from.
> >> - make the "Strech using current extent" method honour the way min/max
> are
> >> computed in the min/max settings instead of using systematically the
> >> min/max.
> >> So when "Updated canvas" would be selected, it would have no (extra)
> >> effect as
> >> expected.
> >>
> >> Any opinions ?
> >>
> >> Even
> >>
> >> --
> >> Spatialys - Geospatial professional services
> >> http://www.spatialys.com
> >>
> >> ___
> >> Qgis-developer mailing list
> >> Qgis-developer@lists.osgeo.org
> >> List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
> >> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
> >
> >
> > ___
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> > Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
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Re: [Qgis-developer] Feedback for contrast enhancement ... enhancements ?

[Nyall Dawson]

On 2 September 2016 at 21:50, G. Allegri  wrote:
> +1
>
> I would also make min/max the default option, because I've has many users
> (mostly newcomers) were struggling too find out why some pixels were not
> displaying as expected. It was because the statistics weren't including
> some, few, important pixels.

Yes please! There's so many users on stackexchange who get confused
with this same issue.

Nyall

> Anyway I know that, generally, cutting the tails provide a better visual
> result.
>
> giovanni
>
>
> Il 02/set/2016 12:39, "Even Rouault"  ha
> scritto:
>>
>> Hi,
>>
>> There has been interest expressed to improve the usability of the contrast
>> enhancement function. Basically there are workflows where you want the
>> min/max
>> values used by contrast enhancement to be updated each time you pan or
>> zoom
>> the canvas. From what I've seen, here's what currently exists:
>> - a long method (6 clicks): through the Style tab of the layer properties
>> - a faster method (2 clicks): through the "Strech using current extent" of
>> the
>> contextual menu of the layer panel.
>>
>> When you have several rasters loaded, even the 2-click method is
>> inconvenient,
>> so there's a need for a 0-click solution (once the layers have been
>> configured)
>>
>> Another shortcoming in the current implementation is that the settings of
>> the
>> "Load min/max values" foldable group are not persistant, which requires
>> re-
>> setting them if you're not happy with the default Cumlative count cut
>> method.
>> And if you use the "Strech using current extent" menu item, the genuine
>> min/max values are used (not the 2-98% cumulative count cut)
>>
>> So I was thinking to something along the following lines:
>> - make the min/max settings persistant
>> - remove the "Load" button and "Clip extent to canvas" checkbox, and
>> replace
>> them by 3 radio buttons to determine the scope of statistics : "Whole
>> raster",
>> "Current canvas" and "Updated canvas". See the attached
>> proposal_min_max.png.
>> The function of the Load button would be replaced by the general Apply /
>> OK
>> buttons.
>> - when the user manually enters the min/max values, the 2 groups of radio
>> buttons (method to compute min/max and scope of statistics) would be
>> unchecked
>> so that is is clear that they don't come from computed statistics. I also
>> think that when you select "Current canvas", once the Apply/OK buttons
>> have
>> been pushed, the checked state of Current canvas shouldn't be saved. This
>> way
>> when you display the layer properties you have a good idea of where the
>> current min/max values come from.
>> - make the "Strech using current extent" method honour the way min/max are
>> computed in the min/max settings instead of using systematically the
>> min/max.
>> So when "Updated canvas" would be selected, it would have no (extra)
>> effect as
>> expected.
>>
>> Any opinions ?
>>
>> Even
>>
>> --
>> Spatialys - Geospatial professional services
>> http://www.spatialys.com
>>
>> ___
>> Qgis-developer mailing list
>> Qgis-developer@lists.osgeo.org
>> List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>
>
> ___
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> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
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Re: [Qgis-developer] Feedback for contrast enhancement ... enhancements ?

[G. Allegri]

+1

I would also make min/max the default option, because I've has many users
(mostly newcomers) were struggling too find out why some pixels were not
displaying as expected. It was because the statistics weren't including
some, few, important pixels.
Anyway I know that, generally, cutting the tails provide a better visual
result.

giovanni

Il 02/set/2016 12:39, "Even Rouault"  ha
scritto:

> Hi,
>
> There has been interest expressed to improve the usability of the contrast
> enhancement function. Basically there are workflows where you want the
> min/max
> values used by contrast enhancement to be updated each time you pan or zoom
> the canvas. From what I've seen, here's what currently exists:
> - a long method (6 clicks): through the Style tab of the layer properties
> - a faster method (2 clicks): through the "Strech using current extent" of
> the
> contextual menu of the layer panel.
>
> When you have several rasters loaded, even the 2-click method is
> inconvenient,
> so there's a need for a 0-click solution (once the layers have been
> configured)
>
> Another shortcoming in the current implementation is that the settings of
> the
> "Load min/max values" foldable group are not persistant, which requires re-
> setting them if you're not happy with the default Cumlative count cut
> method.
> And if you use the "Strech using current extent" menu item, the genuine
> min/max values are used (not the 2-98% cumulative count cut)
>
> So I was thinking to something along the following lines:
> - make the min/max settings persistant
> - remove the "Load" button and "Clip extent to canvas" checkbox, and
> replace
> them by 3 radio buttons to determine the scope of statistics : "Whole
> raster",
> "Current canvas" and "Updated canvas". See the attached
> proposal_min_max.png.
> The function of the Load button would be replaced by the general Apply / OK
> buttons.
> - when the user manually enters the min/max values, the 2 groups of radio
> buttons (method to compute min/max and scope of statistics) would be
> unchecked
> so that is is clear that they don't come from computed statistics. I also
> think that when you select "Current canvas", once the Apply/OK buttons have
> been pushed, the checked state of Current canvas shouldn't be saved. This
> way
> when you display the layer properties you have a good idea of where the
> current min/max values come from.
> - make the "Strech using current extent" method honour the way min/max are
> computed in the min/max settings instead of using systematically the
> min/max.
> So when "Updated canvas" would be selected, it would have no (extra)
> effect as
> expected.
>
> Any opinions ?
>
> Even
>
> --
> Spatialys - Geospatial professional services
> http://www.spatialys.com
>
> ___
> Qgis-developer mailing list
> Qgis-developer@lists.osgeo.org
> List info: http://lists.osgeo.org/mailman/listinfo/qgis-developer
> Unsubscribe: http://lists.osgeo.org/mailman/listinfo/qgis-developer
>
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[Qgis-developer] Feedback for contrast enhancement ... enhancements ?

[Even Rouault]

Hi,

There has been interest expressed to improve the usability of the contrast 
enhancement function. Basically there are workflows where you want the min/max 
values used by contrast enhancement to be updated each time you pan or zoom 
the canvas. From what I've seen, here's what currently exists:
- a long method (6 clicks): through the Style tab of the layer properties
- a faster method (2 clicks): through the "Strech using current extent" of the 
contextual menu of the layer panel.

When you have several rasters loaded, even the 2-click method is inconvenient, 
so there's a need for a 0-click solution (once the layers have been configured)

Another shortcoming in the current implementation is that the settings of the 
"Load min/max values" foldable group are not persistant, which requires re-
setting them if you're not happy with the default Cumlative count cut method. 
And if you use the "Strech using current extent" menu item, the genuine 
min/max values are used (not the 2-98% cumulative count cut)

So I was thinking to something along the following lines:
- make the min/max settings persistant
- remove the "Load" button and "Clip extent to canvas" checkbox, and replace 
them by 3 radio buttons to determine the scope of statistics : "Whole raster", 
"Current canvas" and "Updated canvas". See the attached proposal_min_max.png. 
The function of the Load button would be replaced by the general Apply / OK 
buttons.
- when the user manually enters the min/max values, the 2 groups of radio 
buttons (method to compute min/max and scope of statistics) would be unchecked 
so that is is clear that they don't come from computed statistics. I also 
think that when you select "Current canvas", once the Apply/OK buttons have 
been pushed, the checked state of Current canvas shouldn't be saved. This way 
when you display the layer properties you have a good idea of where the 
current min/max values come from.
- make the "Strech using current extent" method honour the way min/max are 
computed in the min/max settings instead of using systematically the min/max. 
So when "Updated canvas" would be selected, it would have no (extra) effect as 
expected.

Any opinions ?

Even

-- 
Spatialys - Geospatial professional services
http://www.spatialys.com
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