public void TestCartesianToGC() { // start position of test double latStart = 47.0; double lonStart = 11.0; // 1 arcsec is about 30m => move in 0.3m steps along all 8 axis away from the start position double deltaInc = 0.01 / 3600.0; GeographicPosition pStart = new GeographicPosition(latStart, lonStart, 0); double distance = 0; double direction = 0; Length gcDist = Length.Zero; Angle gcDir; // iterate over the 8 axis (45° increments) for (int signIdx = 0; signIdx < 8; signIdx++) { double dblXSign = 1.0; if (signIdx >= 4 && signIdx <= 6) { dblXSign = -1.0; } else if (signIdx == 3 || signIdx == 7) { dblXSign = 0.0; } double dblYSign = 1.0; if (signIdx >= 2 && signIdx <= 4) { dblYSign = -1.0; } else if (signIdx == 1 || signIdx == 5) { dblYSign = 0.0; } // iterate in 0.3m steps (up to about 150m distance) for (int idx = 1; idx <= 400; idx++) { double delta = idx * deltaInc; GeographicPosition pEnd = new GeographicPosition(latStart + dblYSign * delta, lonStart + dblXSign * delta, 0); InternalDistDir(pStart, pEnd, ref distance, ref direction); GreatCircle.DistAndDir(pStart, pEnd, out gcDist, out gcDir); // compare the two calculation methods Assert.True(Math.Abs(distance - gcDist.Meters) < 1.0, "position accuracy less than 1m"); Assert.True(GreatCircle.AngleDifferenceSignedDegrees(direction, gcDir.Degrees) < 1.0, "direction accuracy less than 1 deg"); // calculate the endpoint with the previously calculated offsets using great circle double dblEndLat = 0; double dblEndLon = 0; GreatCircle.CalcCoords(pStart.Latitude, pStart.Longitude, gcDir.Degrees, gcDist.Meters, out dblEndLat, out dblEndLon); Assert.True(Math.Abs(dblEndLat - pEnd.Latitude) < 1.0, "GC latitude accuracy less than 1m"); Assert.True(GreatCircle.AngleDifferenceSignedDegrees(dblEndLon, pEnd.Longitude) < 1.0, "GC longitude accuracy less than 1m"); // calculate the endpoint with the previously calculated offsets using the cartesic routine GeographicPosition pCalcEnd = InternalExtrapolatePosition(pStart, distance, direction); double dblDeltaX = Math.Abs(pCalcEnd.Longitude - pEnd.Longitude) * GreatCircle.MetersPerDegreeLongitude; double dblDeltaY = Math.Abs(pCalcEnd.Latitude - pEnd.Latitude) * GreatCircle.MetersPerDegreeeLatitude; Assert.True(dblDeltaY < 1.0, "XY latitude accuracy less than 1m"); Assert.True(dblDeltaX < 1.0, "XY longitude accuracy less than 1m"); } } }
private static bool TestDistAndDir(double startlat, double startlon, double endlat, double endlon) { double dist = 0; double dir = 0; GreatCircle.DistAndDir(startlat, startlon, endlat, endlon, out dist, out dir); Angle dirNormalized = Angle.FromDegrees(dir).Normalize(true); if (endlon >= 180) { endlon -= 360; } if (endlon < -180) { endlon += 360; } Assert.True(dist < 30000000, "Distance more than 1/2 times around the earth"); Assert.True(dirNormalized.Degrees >= 0 && dirNormalized.Degrees < 360, "Angle out of bounds"); double reslat = 0; double reslon = 0; GreatCircle.CalcCoords(startlat, startlon, dir, dist, out reslat, out reslon); Angle lon = Angle.FromDegrees(reslon); lon = lon.Normalize(false); Assert.True(reslat >= -90 && reslat <= 90, "Invalid latitude"); Assert.True(lon.Degrees > -180, $"Invalid longitude A {reslon}"); Assert.True(lon.Degrees <= 180, $"Invalid longitude B {reslon}"); double accuracy = 1E-7; if (dist > 100000) { accuracy = 1E-6; } if (dist > 1000000) { accuracy = 1E-6; } if (dist > 10000000) { accuracy = 1E-5; } if (Math.Abs(endlat - reslat) > accuracy) { Console.WriteLine("Error testing: " + startlat + "/" + startlon + " to " + endlat + "/" + endlon + " Distance: " + dist + " Difference in lat: " + (endlat - reslat)); return(false); } if (GreatCircle.AngleDifferenceSignedDegrees(endlon, lon.Degrees) > accuracy) { Console.WriteLine("Error testing: " + startlat + "/" + startlon + " to " + endlat + "/" + endlon + " Distance: " + dist + " Difference in lon: " + (endlon - reslon)); return(false); } return(true); }