// Geocentric course/distance computation
static void advanceRadM(const SGGeoc& geoc, double course, double distance,
SGGeoc& result);
static double courseRad(const SGGeoc& from, const SGGeoc& to);
// Geocentric course/distance computation
static void advanceRadM(const SGGeoc& geoc, double course, double distance,
SGGeoc& result);
static double courseRad(const SGGeoc& from, const SGGeoc& to);