Fiona can't be imported into python37, DLL error

[Andreas Müller]

i falsely posted this on issues.qgis.org, and i think it should be addressed here:

I installed fiona along with qgis3 and python3 via osgeo4w-setup.exe but it throws an exeption:

    C:\OSGeo4W>python3
    Python 3.7.0 (v3.7.0:1bf9cc5093, Jun 27 2018, 04:06:47) [MSC v.1914 32 bit (Inte
    l)] on win32
    Type "help", "copyright", "credits" or "license" for more information.
    >>> import fiona
    Traceback (most recent call last):
    File "<stdin>", line 1, in <module>
    File "C:\OSGeo4W\apps\Python37\lib\site-packages\fiona\__init__.py", line 87,
    in <module>
    from fiona.collection import BytesCollection, Collection
    File "C:\OSGeo4W\apps\Python37\lib\site-packages\fiona\collection.py", line 9,
    in <module>
    from fiona.ogrext import Iterator, ItemsIterator, KeysIterator
    ImportError: DLL load failed: Das angegebene Modul wurde nicht gefunden.

This is often reported as a version conflict with gdal.

[Andreas Müller]

dependency walker tells me, it searches for gdal203.dll, which also could be found as a string inside .pyd files for fiona. So I checked, but it seems we never had this version of gdal in osgeo4w. <= EDIT: I misinterpreted package names, so gdal2.3.x contains gdal203.dll. Also, changing strings inside .pyd files solves the error, may be a workaround...

[jef]

There is also a transitional package gdal203dll.

[Andreas Müller]

i tried, but i got the same error, may be that gdal203 has unresolved dependencies. DependencyWalker tells now that hdf_fw.dll and mfhwf_fw.dll is missing. Hdf_fw.dll was definitely present in former installs though.

[Andreas Müller]

I came across this issue again and now tried both osgeo4w64 and osgeo4w(32). I installed fiona along with gdal203 "et voila": It works with the 64-bit version but fails with 32-bit one.

This is the error i got in the python shell:

>>> import fiona
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "C:\OSGeo4W\apps\Python37\lib\site-packages\fiona\__init__.py", line 87, in <module>
    from fiona.collection import BytesCollection, Collection
  File "C:\OSGeo4W\apps\Python37\lib\site-packages\fiona\collection.py", line 9, in <module>
    from fiona.ogrext import Iterator, ItemsIterator, KeysIterator
ImportError: DLL load failed: Das angegebene Modul wurde nicht gefunden.

Also it would be nice, if gdal203dll would be in "requires" of fiona.

[jef]

• [x86] added "new" hdf420dll-4.2.0r3-1 with DLLs from old hdf4-4.2.0r3-4
• [x86] added dependency hdf420dll to gdal202dll and gdal203dll
• added dependency gdal202dll to python-fiona
• added dependency gdal203dll to python3-fiona

[Andreas Müller]

Thank you very much!