gdal_polygonize returns with a strange error

Question

i'm trying to execute gdal_polygoinize.py command. I have a main python method that takes in input a raster file and a output shapefile, and then calls a method named polygonize.py that builds and try to execute the gdal_polygonize command.

The code is:

format = "ESRI Shapefile"
command_poligonize = "gdal_polygonize.bat " + \
                        + input_raster + ' '\
                         '-f ' + '"' + format + '"'+ \
                         shape_output
status=subprocess.call(command_poligonize, shell=True)

i tryed also with the os.system() method:

os.system(command_poligonize)

Executing the command:

print('DEBUG: comand: ' + command_poligonize)

i obtain the correct gdal_polygonize invocation, like:

gdal_polygonize.py input.tif -f "ESRI Shapefile" output.shp

The error description is the following:

  File "C:\OSGeo4W64\bin\gdal_polygonize.py", line 209, in <module> 
     callback = prog_func )
 File "C:\Python35\lib\site-packages\osgeo\gdal.py", line 1636, in Polygonize
     return _gdal.Polygonize(*args, **kwargs)
 RuntimeError: Object given is not a Python function

Any suggestion?

I tryed to run the command by itself, like:

gdal_polygonize.py input.tif -f "ESRI Shapefile" output.shp

and it return with the following error:

  File "C:\OSGeo4W64\bin\gdal_polygonize.py", line 209, in <module> 
     callback = prog_func )
 File "C:\Python35\lib\site-packages\osgeo\gdal.py", line 1636, in Polygonize
     return _gdal.Polygonize(*args, **kwargs)
 RuntimeError: Object given is not a Python function

I'm using Python35 and Gdal 2.0.2 released 2016/01/26.

Answer 1

Running gdal_polygonize.py on Windows, the problem does seem to be with the callback function (used to show progress in the terminal).

A workaround is to set the -quiet or -q flag, e.g.:

gdal_polygonize.py -q input.tif -f "ESRI Shapefile" output.shp

Answer 2

I had this same problem, the issue is the callback parameter being sent to gdal.Polygonize, if you go into he script and remove it from line 208 it should fix your issue.

Answer 3

I report the respective Qgis code:

gdal_polygonize.bat E:\Sviluppo\features_extraction\test\AIRONE_FPL_NoFlyZone_16bit.tif -f "ESRI Shapefile" E:/Sviluppo/features_extraction/test/output_v2.shp output_v2

it works succesfully.

the gdal_polygonize.bat code is:

@python "%OSGEO4W_ROOT%\bin\gdal_polygonize.py" %*  

It may be that i miss some parameters?