[gdal-dev] Default progression order in JP2OpenJPEG driver

[Jukka Rahkonen]

Even Rouault <even.rouault <at> spatialys.com> writes:

> 
> Le jeudi 05 mars 2015 16:25:53, Jukka Rahkonen a écrit :
> > Hi,
> > 
> > It defaults to "LRCP". Is it really a good selection? JP2KAK defaults to
> > "PRCL" and JP2ECW to "RPCL" which both feels better choices than LRCP. But
> > perhaps it has been considered to be good for OpenJPEG because it must
> > practically be used with tiled output which may guarantee fast locational
> > access even with LRCP.
> 
> Jukka,
> 
> Do you have a reference for which progression order is best for which purpose 
> ?
> The default of the OpenJPEG driver is the default os the openjpeg lib itself.

Not really, it must be tested. Unfortunately different JPEG2000 libraries
behave in different ways. However, typical use of geospatial images means
capturing small excerpts from arbitrary places at variable target pixel
sizes and if the tile size is big then LRCP is guaranteed to be bad. Tiling
may change situation.

Test image should be big enough, like 50000x50000 pixels. Myself I have used
jmeter and Mapserver WMS with 1000 different BBOXes for testing. I am sure
you can write some nice python thing for the purpose.

JPEG2000 defaults are very often made for digital photos and for them LRCP
is OK; actually for such small images any progression order is OK.

-Jukka-