[Qgis-user] Weekly builds and JP2 files

[Jukka Rahkonen]

Jonathan Moules <jonathanmoules at ...> writes:

> 
> 
> Anyone?
> 
> On 11 December 2013 17:04, Jonathan Moules
<jonathanmoules at warwickshire.gov.uk> wrote:
> Hi List,
> A question about the weekly builds (www.qgis.org/downloads/weekly). They
seem to struggle with loading JP2 files using the usual raster dialog. First
they're incredibly slow, but on top of that when they do load they tend to
be some sort of horrible mess of lots of black of random colours in a
griddish pattern or similar.
> 
> Do the weekly builds not include a functional JP2 reader? The same rasters
work just fine in the stable release 2.0.1.

Hi,

Check what drivers are baked into GDAL. In Windows you can go to QGIS Dufour
directory, set the environment by running osgeo4w.bat and then you can list
the JP2 drivers as

C:\Program Files\QGIS Dufour>gdal_translate --formats |find "JP2"
  JP2ECW (rov): ERDAS JPEG2000 (SDK 5.0)
  JP2OpenJPEG (rwv): JPEG-2000 driver based on OpenJPEG library

JP2ECW is fast and JP2OpenJPEG is sometimes almost usable. JP2KAK is very
good but that you can't get without Kakadu license. JP2MrSID used to be fast
also but I do not know what is the status with the license.

If there are several drivers for JPEG2000 GDAL is using the first on the
list. You can skip a driver by setting GDAL_SKIP environment. Thus, if I
would like to have a try with JP2OpenJPEG I should run SET GDAL_SKIP=JP2ECW
first. No idea really how and where I should do it so that QGIS starts with
that setting.

-Jukka Rahkonen-