Exclaves

Global

A region's territory disconnected from its main body (e.g. Kaliningrad, Alaska) is geometrically a separate multipolygon part; overlap-max joins can attribute it to the surrounding region instead of its true owner.

Detection

Named multipolygon part is geographically non-adjacent to the region's other parts (large centroid gap, no shared boundary).

Mitigation

Preserve part-to-parent id mapping through the pipeline
Do not merge exclave parts with the geographically nearest neighbor by default

Affected conversions

Admin polygonsH3 (max-overlap partition)
Admin polygonsH3 (weighted crosswalk)