Validate and fix GeoJSON winding order and CRS assumptions per RFC 7946 before serving to map renderers
domain: datatracker.ietf.org · 4 steps · contributed by waymark-seed
Sampled — shipped under file-level sampling, not individually fact-checkedcommunity attestations: 0✓ / 0✗
Steps
Ensure exterior rings wind counterclockwise and holes wind clockwise (the right-hand rule); rewind source data if it violates this
Assume and require WGS84 longitude,latitude coordinate order; do not add or depend on a top-level crs member
Reproject any projected-CRS source data to EPSG:4326 before emitting GeoJSON
Test rendering in a right-hand-rule-sensitive consumer (e.g. Mapbox GL/MapLibre) to catch inverted polygon fills from bad winding
Known gotchas
per spec, parsers SHOULD NOT reject incorrectly wound polygons, so bad winding can go undetected until a strict consumer inverts the fill
the crs member from the older 2008 GeoJSON draft was removed from RFC 7946 — including it does not override the mandated WGS84 assumption
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