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https://github.com/michaelrausch/Party-Parrots-At-Sea.git
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Haoming Yin
83 lines
3.1 KiB
Java
83 lines
3.1 KiB
Java
package seng302.server.simulator;
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import seng302.server.simulator.mark.Position;
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public class GeoUtility {
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private static double EARTH_RADIUS = 6378.137;
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/**
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* Calculates the euclidean distance between two markers on the canvas using xy coordinates
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*
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* @param p1 first geographical position
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* @param p2 second geographical position
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* @return the distance in meter between two points in meters
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*/
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public static Double getDistance(Position p1, Position p2) {
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double dLat = Math.toRadians(p2.getLat() - p1.getLat());
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double dLon = Math.toRadians(p2.getLng() - p1.getLng());
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double a = Math.pow(Math.sin(dLat / 2), 2.0)
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+ Math.cos(Math.toRadians(p1.getLat())) * Math.cos(Math.toRadians(p2.getLat()))
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* Math.pow(Math.sin(dLon / 2), 2.0);
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double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));
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double d = EARTH_RADIUS * c;
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return d * 1000; // distance from km to meter
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}
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/**
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* Calculates the angle between to angular co-ordinates on a sphere.
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*
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* @param p1 the first geographical position, start point
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* @param p2 the second geographical position, end point
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* @return the initial bearing in degree from p1 to p2, value range (0 ~ 360 deg.).
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* vertical up is 0 deg. horizontal right is 90 deg.
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*
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* NOTE:
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* The final bearing will differ from the initial bearing by varying degrees
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* according to distance and latitude (if you were to go from say 35°N,45°E
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* (≈ Baghdad) to 35°N,135°E (≈ Osaka), you would start on a heading of 60°
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* and end up on a heading of 120°
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*/
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public static Double getBearing(Position p1, Position p2) {
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double dLon = Math.toRadians(p2.getLng() - p1.getLng());
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double y = Math.sin(dLon) * Math.cos(Math.toRadians(p2.getLat()));
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double x = Math.cos(Math.toRadians(p1.getLat())) * Math.sin(Math.toRadians(p2.getLat()))
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- Math.sin(Math.toRadians(p1.getLat())) * Math.cos(Math.toRadians(p2.getLat())) * Math.cos(dLon);
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double bearing = Math.toDegrees(Math.atan2(y, x));
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return (bearing + 360.0) % 360.0;
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}
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/**
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* Given an existing point in lat/lng, distance in (in meter) and bearing
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* (in degrees), calculates the new lat/lng.
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*
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* @param origin the original position within lat / lng
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* @param bearing the bearing in degree, from original position to the new position
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* @param distance the distance in meter, from original position to the new position
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* @return the new position
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*/
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public static Position getGeoCoordinate(Position origin, Double bearing, Double distance) {
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double b = Math.toRadians(bearing); // bearing to radians
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double d = distance / 1000.0; // distance to km
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double originLat = Math.toRadians(origin.getLat());
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double originLng = Math.toRadians(origin.getLng());
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double endLat = Math.asin(Math.sin(originLat) * Math.cos(d / EARTH_RADIUS)
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+ Math.cos(originLat) * Math.sin(d / EARTH_RADIUS) * Math.cos(b));
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double endLng = originLng
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+ Math.atan2(Math.sin(b) * Math.sin(d / EARTH_RADIUS) * Math.cos(originLat),
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Math.cos(d / EARTH_RADIUS) - Math.sin(originLat) * Math.sin(endLat));
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return new Position(Math.toDegrees(endLat), Math.toDegrees(endLng));
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}
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}
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