Wegwichtel/public/js/distance.js
2026-06-16 16:20:09 +02:00

34 lines
1.0 KiB
JavaScript

(function (ns) {
'use strict';
const radians = value => value * Math.PI / 180;
const degrees = value => value * 180 / Math.PI;
const normalizeDegrees = value => (value % 360 + 360) % 360;
ns.Distance = {
meters(a, b) {
const dLat = radians(b.lat - a.lat);
const dLon = radians(b.lon - a.lon);
const h = Math.sin(dLat / 2) ** 2
+ Math.cos(radians(a.lat)) * Math.cos(radians(b.lat)) * Math.sin(dLon / 2) ** 2;
return 2 * 6371000 * Math.asin(Math.sqrt(h));
},
bearing(a, b) {
const lat1 = radians(a.lat);
const lat2 = radians(b.lat);
const dLon = radians(b.lon - a.lon);
const y = Math.sin(dLon) * Math.cos(lat2);
const x = Math.cos(lat1) * Math.sin(lat2)
- Math.sin(lat1) * Math.cos(lat2) * Math.cos(dLon);
return normalizeDegrees(degrees(Math.atan2(y, x)));
},
normalizeDegrees,
format(meters) {
return meters < 1000 ? `${Math.round(meters)} m` : `${(meters / 1000).toFixed(1)} km`;
}
};
}(window.Wegwichtel));