Bug report #778
Displaying raster images extremely slow
|Affected QGIS version:||Regression?:||No|
|Operating System:||Debian||Easy fix?:||No|
|Pull Request or Patch supplied:||Resolution:||fixed|
|Crashes QGIS or corrupts data:||Copied to github as #:||10837|
After updating from 0.8.1 to 0.9 ecw rester images that before were displayed at once now take very long time: 4 images of 9 MB each one take about 8 minutes and images of about 700 MB don't display after one hour.
More information can be found here: http://forum.qgis.org/viewtopic.php?t=461
Reproduced in two machines with debian-testing and reported by other user in windows XP
#7 Updated by cdavilam - over 13 years ago
The problem persists in 44cc1223 (SVN r8224). Now a bug squashing is being planned, I would really appreciate if this bug is resolved, as I need to use ecw rasters in my daily work and it's really annoying to wait so much time each time I move map canvas, having to use other programs too often.
#8 Updated by Maciej Sieczka - over 13 years ago
#9 Updated by cdavilam - over 13 years ago
After some investigation compiling various revisions, I have found this bug was introduced in 4c31165e (SVN r7953). I have attached diff between revisions 7951 and 7952. Log for 4c31165e (SVN r7953) is:
4c31165e (SVN r7953) | ersts | 2008-01-14 04:48:11 +0100 (lun, 14 ene 2008) | 1 line
-Set default contrast enhancement to STRETCH_TO_MIN_MAX
#10 Updated by ersts - about 13 years ago
- Status changed from Feedback to Closed
- Resolution set to fixed
There is now an ability to set the default contrast enhancement that will remain persistent between sessions, which resolves this problem to some extent. If stretching is too slow and not needed, the user can elect not to stretch on initial load.
I think this closes this ticket for QGIS, if there are any upstream issues with GDAL that are also fixed in the future, all the more better.
If this is still not a satisfactory solution, feel free to reopen.