/** * GeoPoint * Copyright 2009 by Michael Peter Christen; mc@yacy.net, Frankfurt a. M., Germany * first published 08.10.2009 on http://yacy.net * * This file is part of YaCy Content Integration * * This library is free software; you can redistribute it and/or * modify it under the terms of the GNU Lesser General Public * License as published by the Free Software Foundation; either * version 2.1 of the License, or (at your option) any later version. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * Lesser General Public License for more details. * * You should have received a copy of the GNU Lesser General Public License * along with this program in the file lgpl21.txt * If not, see . */ package net.yacy.document.geolocalization; public class GeoPoint { public static final double meter = 90.0d / 1.0e7d; // this is actually the definition of 'meter': 10 million meter shall be the distance from the equator to the pole private final long latlon; // using one variable for the coordinate pair saves some space public GeoPoint(double lat, double lon) { this.latlon = (((long) coord2int(lat)) << 32) | (coord2int(lon)); } public GeoPoint(int lat, int lon) { this.latlon = (((long) coord2int(lat / 1e6d)) << 32) | (coord2int(lon / 1e6d)); } public double lon() { return int2coord((int) (this.latlon & (Integer.MAX_VALUE))); } public double lat() { return int2coord((int) (this.latlon >>> 32)); } private static final double maxint = new Double(Integer.MAX_VALUE).doubleValue(); private static final double upscale = maxint / 360.0; private static final int coord2int(double coord) { return (int) ((coord + 180.0) * upscale); } private static final double int2coord(int z) { return (z / upscale) - 180.0; } /** * compute the hash code of a coordinate * this produces identical hash codes for locations that are close to each other */ @Override public int hashCode() { return (int) ((this.latlon & Integer.MAX_VALUE) >> 1) + (int) (this.latlon >> 33); } /** * equality test that is needed to use the class inside HashMap/HashSet */ @Override public boolean equals(final Object o) { if (!(o instanceof GeoPoint)) return false; GeoPoint oo = (GeoPoint) o; return (this.latlon == oo.latlon); } @Override public String toString() { return "[" + this.lat() + "," + this.lon() + "]"; } public static void main(String[] args) { double lat = 13.419444d; double lon = 52.548611d; GeoPoint c = new GeoPoint(lat, lon); System.out.println(c.toString() + " #" + c.hashCode()); System.out.println("error: lat: " + (Math.abs(c.lat() - lat) / meter) + " meter; lon: " + (Math.abs(c.lon() - lon) / meter) + " meter"); } }