Feature: Use geojson feature/geometry id if exists

[Mr-Ixolate]

Feature: Use geojson feature/geometry id if exists

[mattijn]

Thanks for raising the issue! It is a good request and this is already happening if it is a geodataframe, see around here: https://github.com/mattijn/topojson/blob/main/topojson/core/extract.py#L533.

Just make sure that you only do this if the index of the full collection is unique. If you want to do a PR, which will be much appreciated!, you can do this with a simple if/else condition.

Hope that helps! And thanks again for raising the issue!

[Mr-Ixolate]

What would be the expectation if duplicate ids were found?

1. Raise an error, possibly with the duplicate ids and their indexesisted.
2. Fallback to the default id naming convention (feature_{idx}
3. Check each id and append idx to the duplicate ids or something

Edit: shouldn't have tried to type this on mobile

[mattijn]

Maybe best using a new parameter in the Topology() class?

Like:
ignore_index: bool, default False

And then do your suggested option 1 if False (default) and if True your option 2?

[mattijn]

Released as of v1.9