Soo… usearch? Its literally one header file (of what use to be strict c++11). Funnily enough that is what is used in the official duckdb-vss extension.
I think this is just cause it hasn't been implemented in spatial yet. DuckDB is currently going through a pretty big refactor of the way we glob/scan/union multiple files with all the recent focus on data lake formats, but my plan is to get to it in spatial after next release when that part of the code has stabilized a bit.
Im inclined to agree, but unfortunately a huge amount of the existing data and processes in this space does not assume a spheroidal earth and come provided with a coordinate reference system. Ultimately there are also some domains where you got data that you explicitly don't want to interpret using spheroidal semantics, e.g. when working with a city plan - in which case the map _is_ the data model, and you definitely want the angles of a triangle to sum up to 180.
I replied to another comment, but I think a big part is that duckdbs spatial extension provides a SQL interface to a whole suite of standard foss gis packages by statically bundling everything (including inlining the default PROJ database of coordinate projection systems into the binary) and providing it for multiple platforms (including WASM). I.E there are no transitive dependencies except libc.
Yes, DuckDB does a whole lot more, vectorized larger-than-memory execution, columnar compressed storage and a ecosystem of other extensions that make it more than the sum of its parts. But while Ive been working hard on making the spatial extension more performant and more broadly useful (I designdd a new geometry engine this year, and spatial join optimization just got merged on the dev-branch), the fact that you can e.g. convert too and from a myriad of different geospatial formats by utilizing GDAL, transforming through SQL, or pulling down the latest overture dump without having the whole workflow break just cause you updated QGIS has probably been the main killer feature for a lot of the early adopters.
(Discmaimer, I work on duckdb-spatial @ duckdblabs)
I think a big part is that duckdbs spatial extension doesnt have any transitive dependencies (except libc). It statically packages the standard suite of foss gis tools (including a whole database of coordinate systems) for multiple platforms (including WASM) and provides a unified SQL interface to it all.
(Disclaimer, I work on duckdb-spatial @duckdblabs)
Disclaimer: I wrote duckdb-vss