Narrow / sliver polygons

Geometry

Polygons thinner than a cell can yield zero center-contained cells.

Detection

Center-fill returns empty while area > 0.

Mitigation

  • Use intersect mode
  • Increase resolution
  • Seed from boundary vertices

Affected conversions

  • PolygonH3 (center-contained)
  • PolygonH3 (fully-contained)