Benoit Bovy

One limitation, though: Numba's [typed.Dict](https://numba.pydata.org/numba-doc/dev/reference/pysupported.html#typed-dict) currently doesn't support mutable lists as values.

Oh yes that makes sense. We could somehow leverage H3 cells at multiple levels (resolutions) for that case...

Not on my side. There's an example of nearest-neighbor search in https://github.com/joaofig/geo-spoke, although I'm not sure that it is fully vectorized (queries are for one point location at a time)....

> I am wondering if adding support for these R-Tree based selectors would be of interest Yes this would be nice additions! We could add adapters for those R-Tree indexes...

I see, clipping irregular data with a list of geometries is a nice example that `xoak` should support directly or indirectly. `xoak` currently exposes a `.sel` method that is similar...

> The challenge here would be to support the variety of the queries supported by each index (e.g., pygeos.STRTree.query_bulk, sklearn.neighbors.KDTree.query_radius, etc.) through a common API. By common API, I mean...

> s2geometry is a C++ library that seems to be used widely in database managers. I missed [h3](https://github.com/uber/h3), and [h3-py](https://github.com/uber/h3-py).

Another interesting reference: `spatialpandas` has an implementation of a static [Hilbert R-tree](https://en.wikipedia.org/wiki/Hilbert_R-tree) in numba.

Some more related work: [CellTree2d](https://github.com/NOAA-ORR-ERD/cell_tree2d) for cell location in (2D) unstructured grids. I seems to require full grid topology (faces, vertices). Link to the paper: https://escholarship.org/content/qt0vq7q87f/qt0vq7q87f.pdf There is a numba...

Thanks for those additional pointers @Huite! There seems to be a general motivation recently in (re)implementing index trees in numba. I think numba is now mature and featured enough to...