{"type": "FeatureCollection", "_meta": {"__meta__": "synthetic", "disclaimer": "Synthetic demo data inspired by real Baltic geography, MMSI/OUI conventions, and infrastructure. Not real observations.", "dataset": "s6-drone-swarm/swarm_fan", "version": "1.0"}, "features": [{"type": "Feature", "properties": {"featureId": "s6-swarm-fan", "name": "Swarm fan envelope", "note": "Convex envelope of all 6 drone paths"}, "geometry": {"type": "Polygon", "coordinates": [[[25.555, 59.92], [25.555, 60.3], [25.64, 60.28], [25.66, 60.225], [25.7, 60.215], [25.35, 60.14], [25.2, 60.11], [25.555, 59.92]]]}}]}