Export fails with empty data
Export step fails if no data was analysed.
Traceback (most recent call last):
File "<string>", line 1, in <module>
File "/oev/oev/src/osm_element_vectorisation/vectorisation.py", line 111, in vectorise_cli
exit_code = vectorise(settings)
File "/oev/oev/src/osm_element_vectorisation/vectorisation.py", line 85, in vectorise
export(ac_settings)
File "/oev/oev/src/osm_element_vectorisation/export/export.py", line 10, in export
__export_geodata(settings)
File "/oev/oev/src/osm_element_vectorisation/export/export.py", line 19, in __export_geodata
data_gdf.to_file(
File "/home/oev/.cache/pypoetry/virtualenvs/osm-element-vectorisation-S7_AxX7I-py3.8/lib/python3.8/site-packages/geopandas/geodataframe.py", line 1086, in to_file
_to_file(self, filename, driver, schema, index, **kwargs)
File "/home/oev/.cache/pypoetry/virtualenvs/osm-element-vectorisation-S7_AxX7I-py3.8/lib/python3.8/site-packages/geopandas/io/file.py", line 304, in _to_file
schema = infer_schema(df)
File "/home/oev/.cache/pypoetry/virtualenvs/osm-element-vectorisation-S7_AxX7I-py3.8/lib/python3.8/site-packages/geopandas/io/file.py", line 362, in infer_schema
raise ValueError("Cannot write empty DataFrame to file.")
ValueError: Cannot write empty DataFrame to file.
Solution: output warning and exit gracefully