Function expansionToLineString

Builds a GeoJSON LineString from an expanded procedure leg sequence, ready to render as a polyline on a map (e.g. MapLibre, Leaflet).

Coordinates follow the GeoJSON [lon, lat] ordering. Returns undefined when the legs yield fewer than two drawable points, since a LineString requires at least two positions to be valid.

Non-positional legs are skipped (see extractLegPoints), so the line connects only the fix-terminated legs in order. When a procedure mixes positional and non-positional legs the line is an approximation that omits the non-drawable segments rather than a precise flyable track.

import { createProcedureResolver, expansionToLineString } from '@squawk/procedures';

const resolver = createProcedureResolver({ data: procedures });
const expansion = resolver.expand('KDEN', 'AALLE4');
const line = expansion ? expansionToLineString(expansion.legs) : undefined;
if (line) {
  map.addSource('procedure', { type: 'geojson', data: line });
}
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