Ciao Jonathan, please read my comments inline below... Regards, Simone Giannecchini == Our support, Your Success! Visit http://opensdi.geo-solutions.it for more information. ==
Ing. Simone Giannecchini @simogeo Founder/Director GeoSolutions S.A.S. Via Poggio alle Viti 1187 55054 Massarosa (LU) Italy phone: +39 0584 962313 fax: +39 0584 1660272 mob: +39 333 8128928 http://www.geo-solutions.it http://twitter.com/geosolutions_it ------------------------------------------------------- On Tue, Nov 12, 2013 at 9:27 AM, Jonathan Moules <jonathanmou...@warwickshire.gov.uk> wrote: > Hi List, > We've recently taken deliver of some aerial photography. > > As lossless GeoTIFFs, the RedGreenBlue data is 278GB > As a compressed JP2 file the data is 26GB - the JP2 is almost as good as the > GeoTIFFs and comes with pyramids built in. Unless you have an ECW or Kakadu license JP2 reading won't be as fast as GeoTiff, I mean, nowhere near to it :) > > But for speed purposes with GeoServer I've created an imageMosaic of 13 Jpeg > compressed GeoTIFFs with overviews/tiles etc. This comes out at a massive > 106GB and the quality is worse than the JP2 file despite being four times > the size. > > Can anyone advise how I can improve these files to make them smaller > (ideally with better quality too)? I created each of the GeoTIFFs with the > following two commands > > Merge, tile, and compress all at once. >> >> gdal_merge -q -o file_name.tif -of GTiff -co TILED=YES -co BIGTIFF=YES -co >> COMPRESS=JPEG -co JPEG_QUALITY=50 -co BLOCKXSIZE=512 -co BLOCKYSIZE=512 >> --optfile tiff_list.txt I believe quality is too low. This makes the files smaller but also makes the jpeg artifacts quite visibile. I would go with the default which is 75%. Moreover, you should use this switch PHOTOMETRIC= YCBCR to improve JPEG compression. > > > Pyramids >> >> gdaladdo -r average %THIS_DIR%.tif 2 4 8 16 32 64 128 256 This is correct but could be done better. Since the base level is compressed I would compress overviews as well. gdaladdo -r cubic -config COMPRESS_OVERVIEW JPEG --config PHOTOMETRIC_OVERVIEW YCBCR %THIS_DIR%.tif 2 4 8 16 32 64 128 256 This should provide more quality but also relatively small size. > > > > Using JP2 with GDAL is tempting (though supposedly much slower) - but we're > likely to be putting up four band (RGB + Infrared) data, which I think we > can use GeoServer to visualise (still to play with). JP2 can't handle four > bands. Ehm, I am playing with 4 bands JP2 just these days, hence I am not so sure this is true (which means I believe it is not :) ) I am doing some work to improve performance + quality of 16 bits 4 bands imagery, if you move on along the JP2 lines I could make good use of a sample. > > Am I doing something wrong with the GeoTIFF creation? > > Thoughts welcome. > Thanks, > Jonathan > > This transmission is intended for the named addressee(s) only and may > contain sensitive or protectively marked material up to RESTRICTED and > should be handled accordingly. Unless you are the named addressee (or > authorised to receive it for the addressee) you may not copy or use it, or > disclose it to anyone else. If you have received this transmission in error > please notify the sender immediately. All email traffic sent to or from us, > including without limitation all GCSX traffic, may be subject to recording > and/or monitoring in accordance with relevant legislation. > ------------------------------------------------------------------------------ > November Webinars for C, C++, Fortran Developers > Accelerate application performance with scalable programming models. Explore > techniques for threading, error checking, porting, and tuning. Get the most > from the latest Intel processors and coprocessors. See abstracts and > register > http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk > _______________________________________________ > Geoserver-users mailing list > Geoserver-users@lists.sourceforge.net > https://lists.sourceforge.net/lists/listinfo/geoserver-users > ------------------------------------------------------------------------------ November Webinars for C, C++, Fortran Developers Accelerate application performance with scalable programming models. Explore techniques for threading, error checking, porting, and tuning. Get the most from the latest Intel processors and coprocessors. See abstracts and register http://pubads.g.doubleclick.net/gampad/clk?id=60136231&iu=/4140/ostg.clktrk _______________________________________________ Geoserver-users mailing list Geoserver-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/geoserver-users
