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Adding a distance approximation that works great for short distances and

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has a lot less calls to trigonometric functions
This commit is contained in:
DennisOSRM 2012-12-17 11:22:44 +01:00
parent ac06a2ef03
commit 0f106c627b
1 changed files with 19 additions and 18 deletions
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37
DataStructures/Coordinate.h
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@ -57,23 +57,7 @@ inline double ApproximateDistance( const int lat1, const int lon1, const int lat
assert(lon1 != INT_MIN);
assert(lat2 != INT_MIN);
assert(lon2 != INT_MIN);
// static const double DEG_TO_RAD = 0.017453292519943295769236907684886;
// //Earth's quatratic mean radius for WGS-84
// static const double EARTH_RADIUS_IN_METERS = 6372797.560856;
// double latitudeArc = ( lat1/100000. - lat2/100000. ) * DEG_TO_RAD;
// double longitudeArc = ( lon1/100000. - lon2/100000. ) * DEG_TO_RAD;
// double latitudeH = sin( latitudeArc * 0.5 );
// latitudeH *= latitudeH;
// double lontitudeH = sin( longitudeArc * 0.5 );
// lontitudeH *= lontitudeH;
// double tmp = cos( lat1/100000. * DEG_TO_RAD ) * cos( lat2/100000. * DEG_TO_RAD );
// double distanceArc = 2.0 * asin( sqrt( latitudeH + tmp * lontitudeH ) );
// return EARTH_RADIUS_IN_METERS * distanceArc;
//double PI = 3.14159265358979323846;//4.0*atan(1.0);
double RAD = 0.017453292519943295769236907684886;
//std::cout << "RAD: " << RAD << std::endl;
//main code inside the class
double lt1 = lat1/100000.;
double ln1 = lon1/100000.;
double lt2 = lat2/100000.;
@ -94,12 +78,29 @@ inline double ApproximateDistance( const int lat1, const int lon1, const int lat
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_ */