How to get geometry given a cell ID?

[bertday]

Hello, again!

I'm trying to get all hexagon IDs and geometries to cover a polygon at a given resolution. My query to get the IDs looks like:

select
	h3_polygon_to_cells(
		st_setsrid(st_extent(geom), 4326),
		8
	) as id
from boundary

and that's working great! Now I just need to get the geometry for each hexagon. I'm having some trouble finding the right function. I've been trying h3_cells_to_multi_polygon_geometry(), but that seems to return a single geometry for all the hexagons, with no attributes (such as ID).

Is there anyone who might be able to give me a pointer on this? Thanks so much!

[zachasme]

Hi again, Robert!

If you wish to fetch one geometry per cell, I would use h3_polygon_to_cells, for example:

WITH cells AS ( 
	SELECT
		h3_polygon_to_cells(
			st_setsrid(st_extent(geom), 4326),
			8
		) AS id
	FROM boundary
) SELECT id, h3_cell_to_boundary_geometry(id) FROM cells;

Cheers!

[bertday]

Amazing, thank you @zachasme! Remembering that one 😊