osrm-backend/DataStructures/Coordinate.h

/*

Copyright (c) 2013, Project OSRM, Dennis Luxen, others
All rights reserved.

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

Redistributions of source code must retain the above copyright notice, this list
of conditions and the following disclaimer.
Redistributions in binary form must reproduce the above copyright notice, this
list of conditions and the following disclaimer in the documentation and/or
other materials provided with the distribution.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR
ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

*/

#ifndef FIXED_POINT_COORDINATE_H_
#define FIXED_POINT_COORDINATE_H_

#include "../DataStructures/MercatorUtil.h"
#include "../Util/StringUtil.h"

#include <cassert>
#include <cmath>
#include <climits>

#include <iostream>

static const double COORDINATE_PRECISION = 1000000.;

struct FixedPointCoordinate {
    int lat;
    int lon;
    FixedPointCoordinate () : lat(INT_MIN), lon(INT_MIN) {}
    explicit FixedPointCoordinate (int lat, int lon) : lat(lat) , lon(lon) {}

    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*COORDINATE_PRECISION ||
            lat <  -90*COORDINATE_PRECISION ||
            lon >  180*COORDINATE_PRECISION ||
            lon < -180*COORDINATE_PRECISION
        ) {
            return false;
        }
        return true;
    }
    bool operator==(const FixedPointCoordinate & other) const {
        return lat == other.lat && lon == other.lon;
    }
};

inline std::ostream & operator<<(std::ostream & out, const FixedPointCoordinate & 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/COORDINATE_PRECISION;
    double ln1 = lon1/COORDINATE_PRECISION;
    double lt2 = lat2/COORDINATE_PRECISION;
    double ln2 = lon2/COORDINATE_PRECISION;
    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 FixedPointCoordinate &c1, const FixedPointCoordinate &c2) {
    return ApproximateDistance( c1.lat, c1.lon, c2.lat, c2.lon );
}

inline double ApproximateEuclideanDistance(const FixedPointCoordinate &c1, const FixedPointCoordinate &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/COORDINATE_PRECISION)*RAD;
    const double lon1 = (c1.lon/COORDINATE_PRECISION)*RAD;
    const double lat2 = (c2.lat/COORDINATE_PRECISION)*RAD;
    const double lon2 = (c2.lon/COORDINATE_PRECISION)*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;
}

static inline void convertInternalLatLonToString(const int value, std::string & output) {
    char buffer[100];
    buffer[11] = 0; // zero termination
    char* string = printInt< 11, 6 >( buffer, value );
    output = string;
}

static inline void convertInternalCoordinateToString(const FixedPointCoordinate & coord, std::string & output) {
    std::string tmp;
    convertInternalLatLonToString(coord.lon, tmp);
    output = tmp;
    output += ",";
    convertInternalLatLonToString(coord.lat, tmp);
    output += tmp;
    output += " ";
}
static inline void convertInternalReversedCoordinateToString(const FixedPointCoordinate & coord, std::string & output) {
    std::string tmp;
    convertInternalLatLonToString(coord.lat, tmp);
    output = tmp;
    output += ",";
    convertInternalLatLonToString(coord.lon, tmp);
    output += tmp;
    output += " ";
}


/* Get angle of line segment (A,C)->(C,B), atan2 magic, formerly cosine theorem*/
template<class CoordinateT>
static inline double GetAngleBetweenThreeFixedPointCoordinates (
    const CoordinateT & A,
    const CoordinateT & C,
    const CoordinateT & B
) {
    const double v1x = (A.lon - C.lon)/COORDINATE_PRECISION;
    const double v1y = lat2y(A.lat/COORDINATE_PRECISION) - lat2y(C.lat/COORDINATE_PRECISION);
    const double v2x = (B.lon - C.lon)/COORDINATE_PRECISION;
    const double v2y = lat2y(B.lat/COORDINATE_PRECISION) - lat2y(C.lat/COORDINATE_PRECISION);

    double angle = (atan2(v2y,v2x) - atan2(v1y,v1x) )*180/M_PI;
    while(angle < 0)
        angle += 360;
    return angle;
}
#endif /* FIXED_POINT_COORDINATE_H_ */