I use OSGeo4W on Windows 7 (64 bit) and included libpng16.dll When I try

C:\OSGeo4W64\bin>gdal_polygonize star.png bla

I get the following error:

ERROR 4: `star.png' does not exist in the file system,
and is not recognised as a supported dataset name.
Unable to open star.png

I copied star.png into C:\OSGeo4W64\bin (this is where gdal_polygonize batch file, python file and compiled python file are located )

What is the mistake?

UPDATE: I found out that I get the same mistake with a TIFF file but it works on JPEGs. Maybe the library/module for PNGs can't be found?

  • 1
    I can't see any mistake and your command works for me. – user30184 Oct 29 '14 at 13:36
  • Try again with the full path name before star.png. – AndreJ Oct 29 '14 at 13:38
  • same :( I tried C:\OSGeo4W64\lib>gdal_polygonize C:\OSGeo4W64\bin\star.png bla – Selphiron Oct 29 '14 at 13:46
  • could it be caused by a wrong or missing environment variable ? I read that you usually add GDAL_DATA variable but I don't habe a gdal/data in my OSGeo4W64 directory.. – Selphiron Oct 29 '14 at 14:25
  • If you are working inside the OSGeo4W Shell, the environment is set correctly. This would apply to all GDAL routines. – AndreJ Oct 30 '14 at 4:51

I don't quite know why but when I accidentally typed .png twice (C:\OSGeo4W64\bin>gdal_polygonize star.png.png bla) it worked.

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