public double calcAzimuth(double lat1, double lon1, double lat2, double lon2) {
        double orientation = Math.PI / 2 - calcOrientation(lat1, lon1, lat2, lon2);
        if (orientation < 0)
            orientation += 2 * Math.PI;

        return Math.toDegrees(Helper.round4(orientation)) % 360;
    }
@Test
    public void testCalcAzimuth() {
        assertEquals(45.0, AC.calcAzimuth(0, 0, 1, 1), 0.001);
        assertEquals(90.0, AC.calcAzimuth(0, 0, 0, 1), 0.001);
        assertEquals(180.0, AC.calcAzimuth(0, 0, -1, 0), 0.001);
        assertEquals(270.0, AC.calcAzimuth(0, 0, 0, -1), 0.001);
        assertEquals(0.0, AC.calcAzimuth(49.942, 11.580, 49.944, 11.580), 0.001);
    }