commit dist folder

gpx/dist/simplify.js

@@ -0,0 +1,126 @@
+import { TrackPoint } from "./gpx";
+const earthRadius = 6371008.8;
+export function ramerDouglasPeucker(points, epsilon = 50, measure = crossarcDistance) {
+    if (points.length == 0) {
+        return [];
+    }
+    else if (points.length == 1) {
+        return [{
+                point: points[0]
+            }];
+    }
+    let simplified = [{
+            point: points[0]
+        }];
+    ramerDouglasPeuckerRecursive(points, epsilon, measure, 0, points.length - 1, simplified);
+    simplified.push({
+        point: points[points.length - 1]
+    });
+    return simplified;
+}
+function ramerDouglasPeuckerRecursive(points, epsilon, measure, start, end, simplified) {
+    let largest = {
+        index: 0,
+        distance: 0
+    };
+    for (let i = start + 1; i < end; i++) {
+        let distance = measure(points[start], points[end], points[i]);
+        if (distance > largest.distance) {
+            largest.index = i;
+            largest.distance = distance;
+        }
+    }
+    if (largest.distance > epsilon && largest.index != 0) {
+        ramerDouglasPeuckerRecursive(points, epsilon, measure, start, largest.index, simplified);
+        simplified.push({ point: points[largest.index], distance: largest.distance });
+        ramerDouglasPeuckerRecursive(points, epsilon, measure, largest.index, end, simplified);
+    }
+}
+export function crossarcDistance(point1, point2, point3) {
+    return crossarc(point1.getCoordinates(), point2.getCoordinates(), point3 instanceof TrackPoint ? point3.getCoordinates() : point3);
+}
+function crossarc(coord1, coord2, coord3) {
+    // Calculates the shortest distance in meters 
+    // between an arc (defined by p1 and p2) and a third point, p3.
+    // Input lat1,lon1,lat2,lon2,lat3,lon3 in degrees.
+    const rad = Math.PI / 180;
+    const lat1 = coord1.lat * rad;
+    const lat2 = coord2.lat * rad;
+    const lat3 = coord3.lat * rad;
+    const lon1 = coord1.lon * rad;
+    const lon2 = coord2.lon * rad;
+    const lon3 = coord3.lon * rad;
+    // Prerequisites for the formulas
+    const bear12 = bearing(lat1, lon1, lat2, lon2);
+    const bear13 = bearing(lat1, lon1, lat3, lon3);
+    let dis13 = distance(lat1, lon1, lat3, lon3);
+    let diff = Math.abs(bear13 - bear12);
+    if (diff > Math.PI) {
+        diff = 2 * Math.PI - diff;
+    }
+    // Is relative bearing obtuse?
+    if (diff > (Math.PI / 2)) {
+        return dis13;
+    }
+    // Find the cross-track distance.
+    let dxt = Math.asin(Math.sin(dis13 / earthRadius) * Math.sin(bear13 - bear12)) * earthRadius;
+    // Is p4 beyond the arc?
+    let dis12 = distance(lat1, lon1, lat2, lon2);
+    let dis14 = Math.acos(Math.cos(dis13 / earthRadius) / Math.cos(dxt / earthRadius)) * earthRadius;
+    if (dis14 > dis12) {
+        return distance(lat2, lon2, lat3, lon3);
+    }
+    else {
+        return Math.abs(dxt);
+    }
+}
+function distance(latA, lonA, latB, lonB) {
+    // Finds the distance between two lat / lon points.
+    return Math.acos(Math.sin(latA) * Math.sin(latB) + Math.cos(latA) * Math.cos(latB) * Math.cos(lonB - lonA)) * earthRadius;
+}
+function bearing(latA, lonA, latB, lonB) {
+    // Finds the bearing from one lat / lon point to another.
+    return Math.atan2(Math.sin(lonB - lonA) * Math.cos(latB), Math.cos(latA) * Math.sin(latB) - Math.sin(latA) * Math.cos(latB) * Math.cos(lonB - lonA));
+}
+export function projectedPoint(point1, point2, point3) {
+    return projected(point1.getCoordinates(), point2.getCoordinates(), point3 instanceof TrackPoint ? point3.getCoordinates() : point3);
+}
+function projected(coord1, coord2, coord3) {
+    // Calculates the point on the line defined by p1 and p2
+    // that is closest to the third point, p3.
+    // Input lat1,lon1,lat2,lon2,lat3,lon3 in degrees.
+    const rad = Math.PI / 180;
+    const lat1 = coord1.lat * rad;
+    const lat2 = coord2.lat * rad;
+    const lat3 = coord3.lat * rad;
+    const lon1 = coord1.lon * rad;
+    const lon2 = coord2.lon * rad;
+    const lon3 = coord3.lon * rad;
+    // Prerequisites for the formulas
+    const bear12 = bearing(lat1, lon1, lat2, lon2);
+    const bear13 = bearing(lat1, lon1, lat3, lon3);
+    let dis13 = distance(lat1, lon1, lat3, lon3);
+    let diff = Math.abs(bear13 - bear12);
+    if (diff > Math.PI) {
+        diff = 2 * Math.PI - diff;
+    }
+    // Is relative bearing obtuse?
+    if (diff > (Math.PI / 2)) {
+        return coord1;
+    }
+    // Find the cross-track distance.
+    let dxt = Math.asin(Math.sin(dis13 / earthRadius) * Math.sin(bear13 - bear12)) * earthRadius;
+    // Is p4 beyond the arc?
+    let dis12 = distance(lat1, lon1, lat2, lon2);
+    let dis14 = Math.acos(Math.cos(dis13 / earthRadius) / Math.cos(dxt / earthRadius)) * earthRadius;
+    if (dis14 > dis12) {
+        return coord2;
+    }
+    else {
+        // Determine the closest point (p4) on the great circle
+        const f = dis14 / earthRadius;
+        const lat4 = Math.asin(Math.sin(lat1) * Math.cos(f) + Math.cos(lat1) * Math.sin(f) * Math.cos(bear12));
+        const lon4 = lon1 + Math.atan2(Math.sin(bear12) * Math.sin(f) * Math.cos(lat1), Math.cos(f) - Math.sin(lat1) * Math.sin(lat4));
+        return { lat: lat4 / rad, lon: lon4 / rad };
+    }
+}