h3shape_to_cells_experimental overlap without border?

[erikvanoosten]

Hi, I noticed that h3.h3shape_to_cells_experimental(h3shape, resolution, contain='overlap') includes tiles that only share a border with the input h3shape.

This leads to weird things like not being able to go from tiles to a geometry and then back to tiles:

santa_fe_res7 = ["8748d8732ffffff", "8748d8730ffffff", "8748d8735ffffff"]
geometry = h3.cells_to_h3shape(santa_fe_res7, tight=True)
tiles = h3.h3shape_to_cells_experimental(geometry, resolution=7, contain='overlap')
assert tiles == santa_fe_res7  # FAILS

tiles contains the 3 input tiles, and all direct neighbors.

My use case is to find all resolution 9 tiles that (partially) overlap a resolution 7 tile.

For this, the 2 tiles circled in red should not be selected.

This all leads to this question: how can we select the tiles that overlap with the contents of a geometry (that is, ignoring its border)?

[erikvanoosten]

For context, getting the resolution 9 child tiles is not what I need because these child tiles do not fully cover the resolution 7 tiles.

The result I am after is: