Ultimately I'd like to be able to compare to Shapely's STRtree + predicate query function, which is one of my favorite things in Shapely, and I use it all the time.

Is there an example of using this for spatial joins or to speed up spatial predicates (esp. via Python wrapper)? I saw mention in the docs that it was being used in geoarrow-rs for that, but couldn't easily find an example/tests/implementation. Is this in the in-progress spatial-join branch?

Great writeup, thank you for sharing! I have indeed been wondering how RTree is implemented in Flatbush; while excellent, I found it a little cryptic and this helped make it more accessible.