[gdal-dev] Troubleshooting palette management. Potential bug in palette for overviews?

[Daniele Romagnoli]

Hi Richard,
when investigating on an issue very similar to the ones you have reported,
I have discovered that the problem was in the color map.
You may take a look on the details of my original report:
https://lists.osgeo.org/pipermail/gdal-dev/2016-November/045589.html.

The outcome of that problem was that the colors of the geotiff with palette
+ overviews were changing when zooming out from native to overview.
So I think it could be related since, at the end, the transparent entry is
a color itself.

Daniele








On Thu, Mar 8, 2018 at 4:17 PM, Richard 🌍 Duivenvoorde <richard at duif.net>
wrote:

> On 08-03-18 15:55, Even Rouault wrote:
> > On jeudi 8 mars 2018 15:32:09 CET Daniele Romagnoli wrote:
> >> I'm resurrecting this old post since I think we have (GeoServer) been
> hit
> >> by that problem again (although I'm not 100% sure about that).
> >
> > http://osgeo-org.1560.x6.nabble.com/Geotiff-pyramids-
> non-transparant-while-o
> >> riginal-is-transparent-td5357343.html
>
> >> Do you know if there is any plan to fix https://trac.osgeo.org/gdal/
> ticket/2213?
> >
> > there was no "plan", but seing this is a 10-year long lasting issue made
> > me sad, so I've just pushed a fix... As suggested in this discussion
> > thread, I've used 257 as factor for multiplication/division hopefully
> > all over the relevant places.
>
> Thanks Even!
>
> Looking at the patch, I understand it will fix a color map change, but
> (my) original Geoserver issue [0] was about the transparency in
> (apparently) the generated overview images.
>
> Is that relevant in this case? Or is this only about actual colors?
>
> Regards,
>
> Richard Duivenvoorde
>
> [0]
> http://osgeo-org.1560.x6.nabble.com/Geotiff-pyramids-
> non-transparant-while-original-is-transparent-td5357343.html
>



-- 
Regards,
Daniele Romagnoli
==
GeoServer Professional Services from the experts! Visit http://goo.gl/it488V
for more information.
==

Ing. Daniele Romagnoli
Senior Software Engineer

GeoSolutions S.A.S.
Via di Montramito 3/A
55054  Massarosa (LU)
Italy
phone: +39 0584 962313
fax:      +39 0584 1660272

http://www.geo-solutions.it
http://twitter.com/geosolutions_it

-------------------------------------------------------
AVVERTENZE AI SENSI DEL D.Lgs. 196/2003
Le informazioni contenute in questo messaggio di posta elettronica e/o
nel/i file/s allegato/i sono da considerarsi strettamente riservate. Il
loro utilizzo è consentito esclusivamente al destinatario del messaggio,
per le finalità indicate nel messaggio stesso. Qualora riceviate questo
messaggio senza esserne il destinatario, Vi preghiamo cortesemente di
darcene notizia via e-mail e di procedere alla distruzione del messaggio
stesso, cancellandolo dal Vostro sistema. Conservare il messaggio stesso,
divulgarlo anche in parte, distribuirlo ad altri soggetti, copiarlo, od
utilizzarlo per finalità diverse, costituisce comportamento contrario ai
principi dettati dal D.Lgs. 196/2003.

The information in this message and/or attachments, is intended solely for
the attention and use of the named addressee(s) and may be confidential or
proprietary in nature or covered by the provisions of privacy act
(Legislative Decree June, 30 2003, no.196 - Italy's New Data Protection
Code).Any use not in accord with its purpose, any disclosure, reproduction,
copying, distribution, or either dissemination, either whole or partial, is
strictly forbidden except previous formal approval of the named
addressee(s). If you are not the intended recipient, please contact
immediately the sender by telephone, fax or e-mail and delete the
information in this message that has been received in error. The sender
does not give any warranty or accept liability as the content, accuracy or
completeness of sent messages and accepts no responsibility  for changes
made after they were sent or for other risks which arise as a result of
e-mail transmission, viruses, etc.
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://lists.osgeo.org/pipermail/gdal-dev/attachments/20180308/6972389f/attachment.html>