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GPXSee/src/common/greatcircle.cpp

24 lines
770 B
C++

#include "greatcircle.h"
Coordinates GreatCircle::pointAt(const Coordinates &c1, const Coordinates &c2,
double f)
{
double lat1 = deg2rad(c1.lat());
double lon1 = deg2rad(c1.lon());
double lat2 = deg2rad(c2.lat());
double lon2 = deg2rad(c2.lon());
double cosLat1 = cos(lat1);
double cosLat2 = cos(lat2);
double d = 2 * asin(sqrt(pow((sin((lat1 - lat2) / 2)), 2) + cosLat1
* cosLat2 * pow(sin((lon1 - lon2) / 2), 2)));
double sinD = sin(d);
double A = sin((1.0-f)*d) / sinD;
double B = sin(f*d) / sinD;
double x = A * cosLat1 * cos(lon1) + B * cosLat2 * cos(lon2);
double y = A * cosLat1 * sin(lon1) + B * cosLat2 * sin(lon2);
double z = A * sin(lat1) + B * sin(lat2);
return Coordinates(rad2deg(atan2(y, x)), rad2deg(atan2(z, sqrt(x*x + y*y))));
}