As others have noted, your image performance is very bad. You can convert your JP2 to TIFF with internal JPEG compression with gdal_translate. You will get similar file size but I think much better performance. Something like:
gdal_translate sourceImage.jp2 outputImage.tif -co COMPRESS=JPEG -co PHOTOMETRIC=YCBCR You can also use GDAL to add overviews (pyramid) with the following: gdaladdo.exe --config COMPRESS_OVERVIEW JPEG -r average -ro --config PHOTOMETRIC_OVERVIEW YCBCR --config INTERLEAVE_OVERVIEW PIXEL sourceImage.jp2f 2 4 8 16 32 64 128 Rich On Thu, Jul 12, 2012 at 4:11 AM, Tim Sutton <li...@linfiniti.com> wrote: > Hi > > On Thu, Jul 12, 2012 at 12:01 PM, Bernhard Ströbl > <bernhard.stro...@jena.de> wrote: >> >> >> Am 12.07.2012 11:48, schrieb watercr...@gmx.de: >> >>> Hi, >>> >>> has anyone tested the performance of qgis on android. >>> >>> I want to collect and store the position of 50 trouts tagged with radio >>> transmitters directly in the field. >>> >>> >>> What I did so far: >>> I have to aim at the targets from different locations at the river bank. >>> What I do now is simply draw lines on printed orthophotos. The fish is >>> located where the lines intersect. It is always quite a mess to >>> determine your own position. I could save the origin with a gps-device >>> but this takes too much time, would include "postprocessing" and adding >>> another step will increase the source of error. >>> >>> ... and it is not possible to walk into the stream ... >>> >>> >>> I am thinking of using a tablet, locally store the orthophotos (5 to 8 >>> pieces, format: .jp2, each around 130 MB) and save the points (e.g. >>> postgis). All metadata could be entered at once. No paper work. I know >>> where I am and can easily store, edit,.. fish data in the field. >>> >>> But I am bit worried about the performance. I takes about two til four >>> minutes to load those raster-layers at my desktop (Ubuntu 12.04, 16GB >>> Ram, QuadCore,...). The performance appears very poor. >> >> >> This is weird. I am not a specialist with raster formats but one of my >> aerial photos (geotif) 281 MB loads and displays within seconds, this is >> with pyramids (maybe you need to build these?) >> I even put some 50 of these photos into a GDAL virtual raster (VRT), it >> takes some 20 seconds to load but displays almost immediately. >> My machine is similar to yours hardwarewise (less RAM, though) running >> OpenSUSE 64 bit. >> > > I think the jp2 drivers are quite slow. A nice solution is to load > your rasters into an mbtiles sqlite database - its not the best for > size, but its very good for performance. > > Note it needs a recent (unreleased?) version of GDAL.. Otherwise > convert your data to tiffs as Bernhard has done and optimise them for > performace by e.g. creating pyramids. > > Regards > > Tim > >> Bernhard >> >> >>> >>> What can I expect from a tablet solution? Anything missing in my chain >>> of thoughts? >>> >>> I really appreciate any hints, ideas ,..I also would like to contribute >>> my experience as a case study for the qgis-website. >>> >>> Regards, >>> Jens >>> _______________________________________________ >>> Qgis-user mailing list >>> Qgis-user@lists.osgeo.org >>> http://lists.osgeo.org/mailman/listinfo/qgis-user >>> >>> >> >> >> __________ Information from ESET Mail Security, version of virus signature >> database 7291 (20120712) __________ >> >> The message was checked by ESET Mail Security. >> http://www.eset.com >> >> >> >> _______________________________________________ >> Qgis-user mailing list >> Qgis-user@lists.osgeo.org >> http://lists.osgeo.org/mailman/listinfo/qgis-user > > > > -- > Tim Sutton - QGIS Project Steering Committee Member (Release Manager) > ============================================== > Please do not email me off-list with technical > support questions. Using the lists will gain > more exposure for your issues and the knowledge > surrounding your issue will be shared with all. > > Visit http://linfiniti.com to find out about: > * QGIS programming and support services > * Mapserver and PostGIS based hosting plans > * FOSS Consulting Services > Skype: timlinux > Irc: timlinux on #qgis at freenode.net > ============================================== > _______________________________________________ > Qgis-user mailing list > Qgis-user@lists.osgeo.org > http://lists.osgeo.org/mailman/listinfo/qgis-user -- Richard Greenwood richard.greenw...@gmail.com www.greenwoodmap.com _______________________________________________ Qgis-user mailing list Qgis-user@lists.osgeo.org http://lists.osgeo.org/mailman/listinfo/qgis-user