Multiband grey in master?

classic Classic list List threaded Threaded
7 messages Options
Reply | Threaded
Open this post in threaded view
|

Multiband grey in master?

Régis Haubourg
Hi all,
regarding to recent modifications in raster styling [0], I was wondering if multiband grey is possible in QGIS.

I usually have topo maps in RGB. It is very handy to switch them to grayscale styling so that vector overlays are well highlighted. I currently didn't find how to do this. I can only have grayscale for one band. The result is not good since red , green or blue band signals are really not supporting the right info. This is existing in Mapinfo and other softs seamlessly.
Did I miss something?



[0]http://hub.qgis.org/issues/6598
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Radim Blazek-2
On Tue, Dec 18, 2012 at 2:23 PM, haubourg
<[hidden email]> wrote:

> Hi all,
> regarding to recent modifications in raster styling [0], I was wondering if
> multiband grey is possible in QGIS.
>
> I usually have topo maps in RGB. It is very handy to switch them to
> grayscale styling so that vector overlays are well highlighted. I currently
> didn't find how to do this. I can only have grayscale for one band. The
> result is not good since red , green or blue band signals are really not
> supporting the right info. This is existing in Mapinfo and other softs
> seamlessly.
> Did I miss something?

Currently that is not possible, AFAIK. I am not sure where it should
go. It may be also useful for color data sources (WMS). In theory it
is possible to add a new filter implementing raster interface and plug
it into the pipe after renderer, but it seems to be overkill too me.
So probably just a new options for multiband color and color data
renderers should be implemented.

Radim

>
>
> [0] http://hub.qgis.org/issues/6598 <http://hub.qgis.org/issues/6598>
>
>
>
> --
> View this message in context: http://osgeo-org.1560.n6.nabble.com/Multiband-grey-in-master-tp5023753.html
> Sent from the Quantum GIS - Developer mailing list archive at Nabble.com.
> _______________________________________________
> Qgis-developer mailing list
> [hidden email]
> http://lists.osgeo.org/mailman/listinfo/qgis-developer
_______________________________________________
Qgis-developer mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-developer
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Régis Haubourg
> So probably just a new options for multiband color and color data renderers
> should be implemented.

Thanks radim for your feedback
Why not 'multiband gray' just like multiband color? It makes sense to me.
Or maybe some users would rather have a checkbox 'show in grayscale' in multiband color screen. Other opinions?
Régis

> -----Message d'origine-----
> De : Radim Blazek [mailto:[hidden email]]
> Envoyé : mardi 18 décembre 2012 16:49
> À : HAUBOURG
> Cc : [hidden email]
> Objet : Re: [Qgis-developer] Multiband grey in master?
>
> On Tue, Dec 18, 2012 at 2:23 PM, haubourg <regis.haubourg@eau-adour-
> garonne.fr> wrote:
> > Hi all,
> > regarding to recent modifications in raster styling [0], I was
> > wondering if multiband grey is possible in QGIS.
> >
> > I usually have topo maps in RGB. It is very handy to switch them to
> > grayscale styling so that vector overlays are well highlighted. I
> > currently didn't find how to do this. I can only have grayscale for
> > one band. The result is not good since red , green or blue band
> > signals are really not supporting the right info. This is existing in
> > Mapinfo and other softs seamlessly.
> > Did I miss something?
>
> Currently that is not possible, AFAIK. I am not sure where it should go. It may
> be also useful for color data sources (WMS). In theory it is possible to add a
> new filter implementing raster interface and plug it into the pipe after
> renderer, but it seems to be overkill too me.
> So probably just a new options for multiband color and color data renderers
> should be implemented.
>
> Radim
>
> >
> >
> > [0] http://hub.qgis.org/issues/6598 <http://hub.qgis.org/issues/6598>
> >
> >
> >
> > --
> > View this message in context:
> > http://osgeo-org.1560.n6.nabble.com/Multiband-grey-in-master-tp5023753
> > .html Sent from the Quantum GIS - Developer mailing list archive at
> > Nabble.com.
> > _______________________________________________
> > Qgis-developer mailing list
> > [hidden email]
> > http://lists.osgeo.org/mailman/listinfo/qgis-developer


_______________________________________________
Qgis-developer mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-developer
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Radim Blazek-2
On Tue, Dec 18, 2012 at 4:52 PM, HAUBOURG
<[hidden email]> wrote:
>> So probably just a new options for multiband color and color data renderers
>> should be implemented.
>
> Thanks radim for your feedback
> Why not 'multiband gray' just like multiband color? It makes sense to me.
> Or maybe some users would rather have a checkbox 'show in grayscale' in multiband color screen.

Your "just like" means a lot of work: new GUI widget, new renderer,
support for this new renderer in raster layer (save restor in/from
project), in renderers registry, in raster layer properties etc.
Technically the renderer would be still multiband color but with
additional grayscale mode flag, but still, it is enough work to do. On
the contrary, to add grayscale flag to multiband color renderer and
widget is easy, because it is only limited to those two classes.

Note also, that the values must first be converted to RGB and then to
grayscale, so all to options for stretching of individual bands must
be there.

In addition, for images which are not in RGB true colors, a user
should have a possibility to tune first bands selection and contrast
enhancement with colors and once the colors are tuned, switch to
grayscale.

It may also be be handy to switch to grayscale and back, according to
situation, without a necessity to change renderer. This could be
useful even for single band pseudocolor and paletted. So it seems
useful for all renderers apart single band gray.

Radim

> Other opinions?
> Régis
>
>> -----Message d'origine-----
>> De : Radim Blazek [mailto:[hidden email]]
>> Envoyé : mardi 18 décembre 2012 16:49
>> À : HAUBOURG
>> Cc : [hidden email]
>> Objet : Re: [Qgis-developer] Multiband grey in master?
>>
>> On Tue, Dec 18, 2012 at 2:23 PM, haubourg <regis.haubourg@eau-adour-
>> garonne.fr> wrote:
>> > Hi all,
>> > regarding to recent modifications in raster styling [0], I was
>> > wondering if multiband grey is possible in QGIS.
>> >
>> > I usually have topo maps in RGB. It is very handy to switch them to
>> > grayscale styling so that vector overlays are well highlighted. I
>> > currently didn't find how to do this. I can only have grayscale for
>> > one band. The result is not good since red , green or blue band
>> > signals are really not supporting the right info. This is existing in
>> > Mapinfo and other softs seamlessly.
>> > Did I miss something?
>>
>> Currently that is not possible, AFAIK. I am not sure where it should go. It may
>> be also useful for color data sources (WMS). In theory it is possible to add a
>> new filter implementing raster interface and plug it into the pipe after
>> renderer, but it seems to be overkill too me.
>> So probably just a new options for multiband color and color data renderers
>> should be implemented.
>>
>> Radim
>>
>> >
>> >
>> > [0] http://hub.qgis.org/issues/6598 <http://hub.qgis.org/issues/6598>
>> >
>> >
>> >
>> > --
>> > View this message in context:
>> > http://osgeo-org.1560.n6.nabble.com/Multiband-grey-in-master-tp5023753
>> > .html Sent from the Quantum GIS - Developer mailing list archive at
>> > Nabble.com.
>> > _______________________________________________
>> > Qgis-developer mailing list
>> > [hidden email]
>> > http://lists.osgeo.org/mailman/listinfo/qgis-developer
>
>
_______________________________________________
Qgis-developer mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-developer
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Régis Haubourg
Radim Blazek-2 wrote
On
the contrary, to add grayscale flag to multiband color renderer and
widget is easy, because it is only limited to those two classes.
Hi Radim,
OK , I had no idea of underlying work. Flag option sounds good too, maybe better in fact.
Thanks for your feedback. I keep that in mind, tell me if any support is required.
Régis
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Radim Blazek-2
On Fri, Dec 21, 2012 at 11:10 AM, haubourg
<[hidden email]> wrote:

> Radim Blazek-2 wrote
>> On
>> the contrary, to add grayscale flag to multiband color renderer and
>> widget is easy, because it is only limited to those two classes.
>
> Hi Radim,
> OK , I had no idea of underlying work. Flag option sounds good too, maybe
> better in fact.
> Thanks for your feedback. I keep that in mind, tell me if any support is
> required.

For now, please create a new issue.

Radim

> Régis
>
>
>
>
> --
> View this message in context: http://osgeo-org.1560.n6.nabble.com/Multiband-grey-in-master-tp5023753p5024285.html
> Sent from the Quantum GIS - Developer mailing list archive at Nabble.com.
> _______________________________________________
> Qgis-developer mailing list
> [hidden email]
> http://lists.osgeo.org/mailman/listinfo/qgis-developer
_______________________________________________
Qgis-developer mailing list
[hidden email]
http://lists.osgeo.org/mailman/listinfo/qgis-developer
Reply | Threaded
Open this post in threaded view
|

Re: Multiband grey in master?

Régis Haubourg