gdal_polygonize missing

[lutra]

it seems that actually the installer do not install the gdal_polygonize script when choosing the gdal 1.6 version.

The lack of this tool do not allow the use of the "polygonize" tool in the "gdal tools" qgis plugin.

[warmerdam]

On review, it appears gdal_polygonize is being installed as part of the gdal16 package.

However, since GDAL 1.6 is not the primary GDAL version it is only put in C:\OSGeo4W\apps\gdal-16\bin which is only in the path after you run the gdal16.bat script.

I think if QGIS's gdal tools intend to run the 1.6 tools, this bin directory should be prepended to the path in some fashion for qgis.

[lutra]

Hi,

However, since GDAL 1.6 is not the primary GDAL version it is only put in C:\OSGeo4W\apps\gdal-16\bin which is only in the path after you run the gdal16.bat script.

strange, I cannot find gdal_poligonize anywhere in my osgeo4w installation that includes gdal-16

[jef]

Short diagnostic:

1. The batch files used to spawn qgis call gdal16.bat
2. gdal_polygonize(.bat) is a batch file in apps/gdal-16/bin
3. calling gdal_polygonize from the QGIS' GRASS shell (just for the environment) gives:

   Traceback (most recent call last):
     File "C:\OSGeo4W\apps\gdal-16\bin\gdal_polygonize.py", line 34, in <module>
       import gdal, ogr, osr
     File "C:\OSGeo4W\apps\Python25\lib\site-packages\gdal.py", line 2, in <module>
   
     File "C:\OSGeo4W\apps\Python25\lib\site-packages\osgeo\gdal.py", line 7, in <module>
   ImportError: No module named _gdal
   

4. Looks like the PYTHONPATH is messed up somehow %OSGEO4W_ROOT%\apps\gdal-16\pymod is missing. Interestingly %OSGEO4W_ROOT%\apps\gdal-16\bin is in the PATH.
5. running gdal16.bat again prepends it to the PYTHONPATH and gdal_polygonize works.

[jef]

Replying to jef:

1. Looks like the PYTHONPATH is messed up somehow %OSGEO4W_ROOT%\apps\gdal-16\pymod is missing. Interestingly %OSGEO4W_ROOT%\apps\gdal-16\bin is in the PATH.

Hm, but import gdal works in the python console as sys.path contains %OSGEO4W_ROOT%\apps\gdal-16\pymod.

[warmerdam]

I see gdal_polygonize.py and gdal_polygonize.bat in the gdal-16-python tar file. I trust this package is installed?

From the above comments it appears the problem is related to transporting the right environment to qgis on startup.

[brushtyler]

In OsGEO4W installation, the gdal_polygonize.bat is in the gdal-16-python package.

If the gdal-16-python package is installed, running either qgis-dev.bat (after installing the qgis-dev package) or qgis.bat (after running gdal16.bat to set env vars), the polygonize tool works fine.