GeoParquet backend

[nicokant]

Would be great if it was possible to serve tiles based on a geoparquet file.

This could be implemented for example using duckdb with the spatial extension, which has ST_ (almost) compatible functions.

[CommanderStorm]

spec

Geoparquet does not have the concept of levels..

Therefore the best we could do is send out a 2d index into the geoparquet..
I am a bit unsure if this is desirable..

As far as I rememeber what it does have is lightweight indexes allowing to not read the entire file for a query.
Since there is no guarantee on sorting though.. this might be not be effective at all leading to an entire table-scan for quite simple operations..

For good performance, support for geoparquet sources like Overture Maps does need a tile generation step like https://github.com/onthegomap/planetiler

Unsure if adding it makes sense..
What would you like to achive? Would simple 2d slicing suffice or would you require simplification at higher zoom levels?