BUG: Exporting a GeoDataframe with column 'fid' to GeoPackage will delete that column

Steps:

1. Create a GeoDataframe with a column 'fid'

2. Export as a GeoPackage using to_file()

3. Read the exported GeoPackage

Bug

The 'fid' column should exist, but is missing.

Hunches

A scan of both the GeoPandas and the Fiona source code reveal no reason this bug should occur, so I suspect that it’s actually an issue with GDAL.

[theroggy]

I forgot about this back then… but a new case where a solution for this would have made life a lot easier arrived…

So, in response to @jorisvandenbossche: I think your second option sounds great. It is safe backwards-compatibility wise, and as it is an index, it sounds reasonable that it would end up as the index of the resulting GeoDataFrame as well.

I also noticed pyogrio.read_dataframe supports it already (on the master branch, not yet in the released latest version), via a parameter called “fid_as_index=False”: https://pyogrio.readthedocs.io/en/latest/api.html#geopandas-integration

[jorisvandenbossche]

I am still a bit hesitant to always convert the id to an "fid" column, when reading from a GeoPackage file: 1) it introduces GPKG specific code in geopandas and 2) it adds an additional column for all users, also when you actually don’t use/need it.

But I certainly understand that, if you want access to the FID of the GeoPackage file, the current situation is quite annoying…

So some option I can think of:

• Simply always include a “fid” column on GPKG file reading (but only for GPKG, I think?)
• Have an option to indicate to preserve the id when reading (then this could be done for all formats, I think, and we don’t necessarily need to make it specific to GPK?)
• Warn users when they write a GeoDataFrame with an “fid” column to GPKG that their column will be lost when reading back (this would be an option if we decide to not change reading, to avoid the roundtrip surprise, but of course in itself doesn’t solve the use case of accessing GPKG’s FID)

Thoughts? Somebody interested in doing a PR for one of those?