Support conversion of attribute layers

[brandones]

Prior to this change, attempting to convert a GDB with attribute layers would result in an error:

~/G/c/data (main|✔) [1] $ fgdb-to-gpkg source.gdb/ source.gpkg          15:54:23      
Converting layers:   0%|                                 | 0/23 [00:00<?, ?it/s]/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198:
 UserWarning: Measured (M) geometry types are not supported. Original type 'Measured 3D MultiPolygon' is converted to 'MultiPolygon Z'                                       
  return ogr_read(                         
Converting layers:   4%|█                        | 1/23 [00:00<00:16,  1.32it/s]/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198:
 UserWarning: Measured (M) geometry types are not supported. Original type 'Measured 3D Point' is converted to 'Point Z'                                                     
  return ogr_read(                         
Converting layers:  13%|███▎                     | 3/23 [00:02<00:14,  1.41it/s]/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198:
 UserWarning: Measured (M) geometry types are not supported. Original type 'Measured 3D MultiLineString' is converted to 'MultiLineString Z'                                 
  return ogr_read(                         
Converting layers:  22%|█████▍                   | 5/23 [00:02<00:07,  2.49it/s]/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198:
 UserWarning: Measured (M) geometry types are not supported. Original type 'Measured 3D MultiLineString' is converted to 'MultiLineString Z'                                 
  return ogr_read(                         
Converting layers:  26%|██████▌                  | 6/23 [00:14<01:00,  3.53s/it]/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198:
 UserWarning: Measured (M) geometry types are not supported. Original type 'Measured 3D MultiPolygon' is converted to 'MultiPolygon Z'                                       
  return ogr_read(                         
/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pyogrio/raw.py:198: RuntimeWarning: organizePolygons() received a polygon with more than 100 parts.
 The processing may be really slow.  You can skip the processing by setting METHOD=SKIP, or only make it analyze counter-clock wise parts by setting METHOD=ONLY_CCW if you c
an assume that the outline of holes is counter-clock wise defined                     
  return ogr_read(                         
Converting layers:  35%|████████▋                | 8/23 [00:19<00:36,  2.44s/it]      
Error converting source.gdb/ to source.gpkg: 'DataFrame' object has no attribute 'to_file'                                                                                   
Traceback (most recent call last):         
  File "/home/brandon/.local/bin/fgdb-to-gpkg", line 8, in <module>                   
    sys.exit(main())                       
             ^^^^^^                        
  File "/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py", line 137, in main                                                                                     
    fgdb_to_gpkg(args.fgdb_path, args.gpkg_path, args.overwrite)                      
  File "/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py", line 116, in fgdb_to_gpkg                                                                             
    convert_layer(fc, fgdb_path, gpkg_path, overwrite, layer_list, **kwargs)          
  File "/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py", line 87, in convert_layer                                                                             
    gdf.to_file(gpkg_path, driver="GPKG", layer=fc, index=False, mode="a", **kwargs)                                                                                         
    ^^^^^^^^^^^                            
  File "/home/brandon/.local/pipx/venvs/fgdb-to-gpkg/lib/python3.12/site-packages/pandas/core/generic.py", line 6299, in __getattr__                                         
    return object.__getattribute__(self, name)                                        
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^                                        
AttributeError: 'DataFrame' object has no attribute 'to_file'. Did you mean: 'to_pickle'? 

With this change, attribute layers are now added to the GeoPackage as expected.

~/G/c/data (main|✔) [1] $ fgdb-to-gpkg source.gdb source.gpkg                                                                              16:21:48                          
Converting layers:   0%|                                                                                                    | 0/23 [00:00<?, ?it/s]/home/brandon/Code/fgdb_to
_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDWaterbody already exists in source.gpkg. Skipping...                                                            
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDPointEventFC already exists in source.gpkg. Skipping...                               
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDPoint already exists in source.gpkg. Skipping...                                      
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDLineEventFC already exists in source.gpkg. Skipping...                                
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDLine already exists in source.gpkg. Skipping...                                       
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDFlowline already exists in source.gpkg. Skipping...                                   
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDAreaEventFC already exists in source.gpkg. Skipping...                                
  warnings.warn(                           
/home/brandon/Code/fgdb_to_gpkg/fgdb_to_gpkg/fgdb_to_gpkg.py:84: UserWarning: Layer NHDArea already exists in source.gpkg. Skipping...                                       
  warnings.warn(                           
Converting layers: 100%|███████████████████████████████████████████████████████████████████████████████████████████| 23/23 [00:48<00:00,  2.10s/it]     

[brandones]

I was unable to write a test, since GeoPandas won't write attribute tables and pyogrio won't write using the OpenFileGDB driver. It might be a good idea to add one or a few very small gdb files to the repository to use as test fixtures, thereby avoiding limitations to writing GDBs.

[philiporlando]

I was unable to write a test, since GeoPandas won't write attribute tables and pyogrio won't write using the OpenFileGDB driver. It might be a good idea to add one or a few very small gdb files to the repository to use as test fixtures, thereby avoiding limitations to writing GDBs.

Thank you for identifying this bug and proposing a solution! I hadn't even considered non-spatial attribute layers when I originally created this. It's frustrating to discover these limitations—GeoPandas not supporting attribute table writing and pyogrio's issues with the OpenFileGDB driver. This feels like an opportunity to explore a standardized approach, perhaps around Arrow tables or something similar. I'll need to look into this further. I've opened #31 for now.

I agree that including a few small .gdb files as test fixtures would be helpful, and this can likely be addressed in a separate PR.

[philiporlando]

This is a nice workaround for the time being. I'll try and explore a more standardized approach and add tests in the long run. Thank you for your contribution!