osrm-backend/DataStructures/Coordinate.h

/*
    open source routing machine
    Copyright (C) Dennis Luxen, others 2010

This program is free software; you can redistribute it and/or modify
it under the terms of the GNU AFFERO General Public License as published by
the Free Software Foundation; either version 3 of the License, or
any later version.

This program 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 General Public License for more details.

You should have received a copy of the GNU Affero General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
or see http://www.gnu.org/licenses/agpl.txt.
 */

#ifndef COORDINATE_H_
#define COORDINATE_H_

#include <climits>
#include <iostream>

struct _Coordinate {
    int lat;
    int lon;
    _Coordinate () : lat(INT_MIN), lon(INT_MIN) {}
    _Coordinate (int t, int n) : lat(t) , lon(n) {}
    void Reset() {
        lat = INT_MIN;
        lon = INT_MIN;
    }
    bool isSet() const {
        return (INT_MIN != lat) && (INT_MIN != lon);
    }
    inline bool isValid() const {
        if(lat > 90*100000 || lat < -90*100000 || lon > 180*100000 || lon <-180*100000) {
            return false;
        }
        return true;
    }
    bool operator==(const _Coordinate & other) const {
        return lat == other.lat && lon == other.lon;
    }
};

inline std::ostream & operator<<(std::ostream & out, const _Coordinate & c){
    out << "(" << c.lat << "," << c.lon << ")";
    return out;
}

inline double ApproximateDistance( const int lat1, const int lon1, const int lat2, const int lon2 ) {
    assert(lat1 != INT_MIN);
    assert(lon1 != INT_MIN);
    assert(lat2 != INT_MIN);
    assert(lon2 != INT_MIN);
    double RAD = 0.017453292519943295769236907684886;
    double lt1 = lat1/100000.;
    double ln1 = lon1/100000.;
    double lt2 = lat2/100000.;
    double ln2 = lon2/100000.;
    double dlat1=lt1*(RAD);

    double dlong1=ln1*(RAD);
    double dlat2=lt2*(RAD);
    double dlong2=ln2*(RAD);

    double dLong=dlong1-dlong2;
    double dLat=dlat1-dlat2;

    double aHarv= pow(sin(dLat/2.0),2.0)+cos(dlat1)*cos(dlat2)*pow(sin(dLong/2.),2);
    double cHarv=2.*atan2(sqrt(aHarv),sqrt(1.0-aHarv));
    //earth's radius from wikipedia varies between 6,356.750 km — 6,378.135 km (˜3,949.901 — 3,963.189 miles)
    //The IUGG value for the equatorial radius of the Earth is 6378.137 km (3963.19 mile)
    const double earth=6372797.560856;//I am doing miles, just change this to radius in kilometers to get distances in km
    double distance=earth*cHarv;
    return distance;
}

inline double ApproximateDistance(const _Coordinate &c1, const _Coordinate &c2) {
    return ApproximateDistance( c1.lat, c1.lon, c2.lat, c2.lon );
}

inline double ApproximateDistanceByEuclid(const _Coordinate &c1, const _Coordinate &c2) {
    assert(c1.lat != INT_MIN);
    assert(c1.lon != INT_MIN);
    assert(c2.lat != INT_MIN);
    assert(c2.lon != INT_MIN);
    const double RAD = 0.017453292519943295769236907684886;
    const double lat1 = (c1.lat/100000.)*RAD;
    const double lon1 = (c1.lon/100000.)*RAD;
    const double lat2 = (c2.lat/100000.)*RAD;
    const double lon2 = (c2.lon/100000.)*RAD;

    const double x = (lon2-lon1) * cos((lat1+lat2)/2.);
    const double y = (lat2-lat1);
    const double earthRadius = 6372797.560856;
    const double d = sqrt(x*x + y*y) * earthRadius;
    return d;
}


#endif /* COORDINATE_H_ */