计算两个GPS坐标的距离 方法二 - C语言

#include <math.h>


#ifdef WIN32
#define round(x) floor(x+0.5) 
#endif /*WIN32*/


#define PI 3.1415926535897
static const double EARTH_RADIUS = 6378.137;


//////////////////////////////////////////////////////////////////////////


double rad(double d)
{
return d * PI / 180.0;
}


double GetDistance(double lat1, double lng1, double lat2, double lng2)
{
double radLat1 = (double)rad(lat1);
double radLat2 = rad(lat2);
double a = radLat1 - radLat2;
double b = rad(lng1) - rad(lng2);
double s = 2 * asin(sqrt(pow(sin(a/2),2) +
cos(radLat1)*cos(radLat2)*pow(sin(b/2),2)));
//
s = s * EARTH_RADIUS;
s = round(s * 10000) / 10000;
return s;
}