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26 lines
823 B
TypeScript
26 lines
823 B
TypeScript
const EARTH_RADIUS_METRES = 6_371_000;
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export interface Coordinates {
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latitude: number;
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longitude: number;
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}
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export const haversineDistanceMetres = (a: Coordinates, b: Coordinates): number => {
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const toRadians = (degrees: number) => (degrees * Math.PI) / 180;
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const deltaLat = toRadians(b.latitude - a.latitude);
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const deltaLng = toRadians(b.longitude - a.longitude);
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const lat1 = toRadians(a.latitude);
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const lat2 = toRadians(b.latitude);
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const h =
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Math.sin(deltaLat / 2) ** 2 +
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Math.cos(lat1) * Math.cos(lat2) * Math.sin(deltaLng / 2) ** 2;
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return 2 * EARTH_RADIUS_METRES * Math.asin(Math.sqrt(h));
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};
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export const formatDistance = (metres: number): string => {
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const km = metres / 1000;
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return km < 10 ? `${km.toFixed(1)} km` : `${Math.round(km)} km`;
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};
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