[gdal-dev] OpenJPEG

[Even Rouault]

Le mardi 22 décembre 2015 14:38:30, Aaron Boxer a écrit :
> On Tue, Dec 22, 2015 at 4:34 AM, Jukka Rahkonen <
> 
> jukka.rahkonen at maanmittauslaitos.fi> wrote:
> > Aaron Boxer <boxerab <at> gmail.com> writes:
> > > This feature would be quite involved: one would have to gather all of
> > > the
> > 
> > layers for
> > 
> > > all of the code blocks in all of the precincts overlapping that
> > 
> > sub-tile,plus the immediately surrounding precincts, run the inverse
> > entropy
> > coder to get the wavelet coefficients, and then do an inverse wavelet
> > transform,with this incomplete set of coefficients.
> > 
> > 
> > I do not claim that I understand GIS but I have a feeling that precincts
> > are
> > designed for a fast ROI access. From
> > http://www2.engr.arizona.edu/~bilgin/publications/SPIE2004_2.pdf
> > 
> > "A precinct is a collection of code-blocks representing some finite
> > spatial extent at some resolution."
> > 
> > Probably gathering the surrounding precincts is unnecessary. Author of
> > Kakadu seems to dislike tiles and it is no wonder that with Kakadu
> > precincts
> > perform well even with archived documents
> > http://www.digitizationguidelines.gov/still-image/documents/Martin.pdf.
> 
> Thanks, that paper was an interesting discussion of optimal encoding
> settings in the archive world.
> 
> What are typical j2k encoding settings in geo-spatial use case ?

That must depend vastly on the producer.

A few examples:

You can download Sentinel-2 products at :
https://scihub.copernicus.eu/s2/#/home
up to 10980x10980 images, 12 bit, with 2048x2048 tiles

Pleidas products :
http://www.geo-airbusds.com/en/23-sample-imagery
Bigger dimension that S-2. Also 12 bit, with 2048x2048 tiles

There are likely sources that are single tiled.

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