Writing an empty GeoDataFrame raises with the OpenFileGDB driver

[alihamdan]

Current behavior

When writing an empty geodataframe to a .gdb file, it raises a DataLayerError: Unsupported geometry type.
Other drivers like GPKG and ESRI Shapefile do not raise on the same geodataframe.

Minimal repro

import geopandas as gpd
import shapely as shp

gdf = gpd.GeoDataFrame({"a": [1.0], "geometry": [shp.Point(0, 0)]}, crs="EPSG:4326")
gdf = gdf.loc[gdf["a"] > 1]  # <- filtering empties the dataframe
gdf.to_file("test.gdb", driver="OpenFileGDB", layer="my_layer")

Expected behavior

Write an empty layer without error.

Versions

pyogrio.__version__: '0.13.0'
pyogrio.__gdal_version_string__: '3.12.4'
pyogrio.__gdal_geos_version__: (3, 14, 1)
gpd.__version__: '1.1.4'
shp.__version__: '2.1.2'

[theroggy]

I've never used file geodatabases myself, but if I understand correctly a layer (or feature class) can only contain one type of geometries (Point,...) and this type should be known when creating a layer.

Another piece of the puzzle is that GeoDataFrames are the other way around: you cannot specify the geometry types at column layer: a layer can always contain any (combination of) geometry types... and so it is not known/specified at geometry column level what type is in it. Hence, once you remove all rows from a GeoDataFrame, the geometry type becomes "any geometrytype".

Combining both... you run into an issue: the GeoDataFrame doesn't have any geometry type information, but when writing a file geodatabase layer (feature class), a specific geometry type is required... so you get an error.

Maybe a workaround: you can pass the geometry_type parameter to to_file to specify the geometrytype, e.g. geometry_type=Point. More information about this parameter can be found here: pyogrio.write_dataframe.

Finally:

• For Geopackage: geopackages support a geometry type where a column can contain any geometry type... so this type is used when writing an empty GeoDataFrame.
• For Shp: shapefiles also don't support mixing geometry types, but - and this is pretty ugly - apparently when writing an empty GeodataFrame, the shapefile seems to be created with geometry_type "LineString".