[gdal-dev] Question on 0th IFD offset when producing a JPEG-Compressed GeoTIFF (GDAL 1.11 vs 2.x)

Daniele Romagnoli daniele.romagnoli at geo-solutions.it
Fri Dec 16 05:29:10 PST 2016

On Fri, Dec 16, 2016 at 1:52 PM, Even Rouault <even.rouault at spatialys.com>

> > Wondering if when generating overviews we still have a problem similar to
> > the one you have fixed in 2.0 or some data-updating issue.
> >
> > These are my hypothesis on what is going on.
> > A simple translate with no overviews makes the file ending at 0x7555 with
> > offset of next IFD saying 0x0000.
> > When you add overviews, it writes a new IFD at 0x7556 with TAG entries,
> > then it encodes something and then it writes a new IFD.
> > At the end, it goes back updating the offset of the 1st overview IFD
> > (0xBBF0) making the one at 0x7556 being not referred anymore.
> > Does it make sense?
> >
> With JPEG compression right ?
Indeed, before sending my previous email I have also tried with:
*gdaladdo -r average --config COMPRESS_OVERVIEW DEFLATE --config
to understand if it was related to JPEG only but, even with these options,
the output overviews were jpeg compressed (I assume there is some kind of
coherency check in gdaladdo).

> I do reproduce something similar to your findings in 2.1 indeed. This no
> longer happens in trunk due to related improvements (
> https://trac.osgeo.org/gdal/wiki/CloudOptimizedGeoTIFF), I made in the
> last couple of weeks (using the same trick of creating a in-memory TIFF
> file to get the JPEG tables and set them direcly on the overview IFD at
> creation time).
Do you think this will be available in other series or does it introduce
new API/major changes which makes it available on 2.2.x only?
Thanks again for your precious feedbacks.


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

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)
phone: +39 0584 962313
fax:      +39 0584 1660272




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/20161216/099ea9b8/attachment.html>

More information about the gdal-dev mailing list