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/*
* Copyright 2014 - 2016 Anton Tananaev (anton@traccar.org)
* Copyright 2016 Andrey Kunitsyn (andrey@traccar.org)
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package org.traccar.helper;
public final class DistanceCalculator {
private DistanceCalculator() {
}
private static final double EQUATORIAL_EARTH_RADIUS = 6378.1370;
private static final double DEG_TO_RAD = Math.PI / 180;
public static double distance(double lat1, double lon1, double lat2, double lon2) {
double dlong = (lon2 - lon1) * DEG_TO_RAD;
double dlat = (lat2 - lat1) * DEG_TO_RAD;
double a = Math.pow(Math.sin(dlat / 2), 2)
+ Math.cos(lat1 * DEG_TO_RAD) * Math.cos(lat2 * DEG_TO_RAD) * Math.pow(Math.sin(dlong / 2), 2);
double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
double d = EQUATORIAL_EARTH_RADIUS * c;
return d * 1000;
}
public static double distanceToLine(
double pointLat, double pointLon, double lat1, double lon1, double lat2, double lon2) {
double d0 = distance(pointLat, pointLon, lat1, lon1);
double d1 = distance(lat1, lon1, lat2, lon2);
double d2 = distance(lat2, lon2, pointLat, pointLon);
if (Math.pow(d0, 2) > Math.pow(d1, 2) + Math.pow(d2, 2)) {
return d2;
}
if (Math.pow(d2, 2) > Math.pow(d1, 2) + Math.pow(d0, 2)) {
return d0;
}
double halfP = (d0 + d1 + d2) * 0.5;
double area = Math.sqrt(halfP * (halfP - d0) * (halfP - d1) * (halfP - d2));
return 2 * area / d1;
}
}
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