/**
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You 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.apache.sis.distance;
// SIS imports
import org.apache.sis.geometry.DirectPosition2D;
/**
* Class to calculate distances on earth surface. Actual calculation code very
* similar to Apache SIS but refractor to allow use of custom classes.
*
* <div class="warning"><b>Warning:</b> This class may change in a future SIS version. Current implementation
* performs computations on a sphere of hard-coded radius. A future implementation should perform computations
* on a given ellipsoid.</div>
*/
public class DistanceUtils {
public static final int EARTH_RADIUS = 6371; // in km
public static final double HALF_EARTH_CIRCUMFERENCE = 20037.58; // in km
/**
* Returns a coordinate on the great circle at the specified bearing.
*
* @param latitude
* the latitude of center of circle
* @param longitude
* the longitude of center of circle
* @param d
* the distance from the center
* @param bearing
* the great circle bearing
* @return a coordinate at the specified bearing
*/
public static DirectPosition2D getPointOnGreatCircle(double latitude, double longitude,
double d, double bearing) {
double angularDistance = d / EARTH_RADIUS;
double lon1 = Math.toRadians(longitude);
double lat1 = Math.toRadians(latitude);
double cosLat = Math.cos(lat1);
double sinLat = Math.sin(lat1);
double sinD = Math.sin(angularDistance);
double cosD = Math.cos(angularDistance);
double brng = Math.toRadians(bearing);
double lat2 = Math.asin((sinLat * cosD) + (cosLat * sinD * Math.cos(brng)));
double lon2 = lon1
+ Math.atan2(Math.sin(brng) * sinD * cosLat, cosD - sinLat
* Math.sin(lat2));
return new DirectPosition2D(Math.toDegrees(lat2), Math.toDegrees(lon2));
}
/**
* Calculates haversine (great circle) distance between two lat/lon
* coordinates.
*
* @param latitude1
* latitude of first coordinate
* @param longitude1
* longitude of first coordinate
* @param latitude2
* latitude of second coordinate
* @param longitude2
* longitude of second coordinate
* @return great circle distance between specified lat/lon coordinates
*/
public static double getHaversineDistance(double latitude1,
double longitude1, double latitude2, double longitude2) {
double longRadian1 = Math.toRadians(longitude1);
double latRadian1 = Math.toRadians(latitude1);
double longRadian2 = Math.toRadians(longitude2);
double latRadian2 = Math.toRadians(latitude2);
double angularDistance = Math.acos(Math.sin(latRadian1)
* Math.sin(latRadian2) + Math.cos(latRadian1) * Math.cos(latRadian2)
* Math.cos(longRadian1 - longRadian2));
return EARTH_RADIUS * angularDistance;
}
}