path: root/libtellurian_coarse_distance_radians.c

/* See LICENSE file for copyright and license details. */
#include "common.h"


double
libtellurian_coarse_distance_radians(double latitude1, double longitude1,
                                     double latitude2, double longitude2)
{
	double h = fma(haversin(longitude2 - longitude1),
	               cos(latitude1) * cos(latitude2),
	               haversin(latitude2 - latitude1));
	return 2.0 * LIBTELLURIAN_AUTHALIC_RADIUS * asin(sqrt(h));
}