[osgeo4w-dev] gdal-python packages & gdal_merge

Frank Warmerdam warmerdam at pobox.com
Fri Oct 10 09:41:55 EDT 2008

fabienne picot wrote:
> I receive this error message:
> --------------------------------------------------------------------------------------------------------
> OSGEO4W home is C:\OSGeo4W
> Microsoft Windows XP [version 5.1.2600]
> (C) Copyright 1985-2001 Microsoft Corp.
> C:\OSGeo4W>gdal_merge
> Traceback (most recent call last):
>   File "C:\OSGeo4W\bin\gdal_merge.py", line 31, in <module>
>     import gdal
>   File "C:\OSGeo4W\apps\Python25\lib\site-packages\gdal.py", line 2, in 
> <module>
>     from osgeo.gdal import deprecation_warn
>   File "C:\OSGeo4W\apps\Python25\lib\site-packages\osgeo\gdal.py", line 
> 7, in <module>
>     import _gdal
> ImportError: DLL load failed with error code 182
> --------------------------------------------------------------------------------------------------------
> + "l'ordinal 109 est introuvable dans la bibliothèque de liaisons 
> dynamiques LIBPQ.dll" (I am sorry, I am french)


Hmm, I'm approaching "stumped".  You mention something about libpq.dll
above.  Was that an error message you received?  Is it possible you have
a copy of libpq.dll in c:\windows\system32 that might be conflicting with
the OSGeo4W one?   If so, could you temporariliy rename it and try
gdal_merge again?

It may be that something like gdalinfo works because it gives top priority
to the DLLs in the same directory as the .exe, while loading python extensions
ends up using a different order of preference for dll searching since the
extension is kept in a distinct directory.  If this is the case it makes
the python aspects sensitive to conflicting pre-installed DLLs in places
like C:\windows\system32 - but I'm really just guessing.

Best regards,

I set the clouds in motion - turn up   | Frank Warmerdam, warmerdam at pobox.com
light and sound - activate the windows | http://pobox.com/~warmerdam
and watch the world go round - Rush    | Geospatial Programmer for Rent

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