/** * Convert geodetic lat/lng to Earth Centered Rotational xyz * * @param Circle $circle * @return Vector */ private function getECRVector(Circle $circle) { $x = $this->earthRadius * (cos(deg2rad($circle->getLat())) * cos(deg2rad($circle->getLng()))); $y = $this->earthRadius * (cos(deg2rad($circle->getLat())) * sin(deg2rad($circle->getLng()))); $z = $this->earthRadius * sin(deg2rad($circle->getLat())); return new Vector(array($x, $y, $z)); }