public void LatLonEqualsTest()
        {
            var p1 = new pt(2.0, 80.0);
            var p2 = new pt(2.05, 80.0);

            Assert.IsFalse(p1.LatLonEquals(p2));
            Assert.IsFalse(p1.LatLonEquals(p2, 0.03));
            Assert.IsTrue(p1.LatLonEquals(p2, 0.06));
        }