長距離獲取不正確的緯度和經度

Question

我正在使用以下功能。

private static Location CoordinateAtADistance(double latOrigin, double lonOrigin, double radius, double angle) 
    { 

     double lonDestination; 
     double R = 6371.0; 
     double d = radius/R; // d = angular distance covered on earth's surface 

     double lat1 = ToRadian(latOrigin); 
     double lon1 = ToRadian(lonOrigin); 
     double brng = ToRadian(angle); 



     double latDestination = lat1 + d * Math.Cos(brng); 
     double dLat = d * Math.Cos(brng); 
     double dPhi = Math.Log(Math.Tan(latDestination/2 + Math.PI/4)/Math.Tan(lat1/2 + Math.PI/4)); 
     double q = (double.IsNaN(dLat/dPhi)) ? dLat/dPhi : Math.Cos(lat1); // E-W line gives dPhi=0 
     double dLon = d * Math.Sin(brng)/q; 
     // check for some daft bugger going past the pole 
     if (Math.Abs(latDestination) > Math.PI/2) 
      latDestination = latDestination > 0 ? Math.PI - latDestination : -(Math.PI - latDestination); 

     lonDestination = (lon1 + dLon +3* Math.PI) % (2 * Math.PI) - Math.PI; 

     Location nextPoint = new Location(); 
     if (angle == 0) 
     { 
      nextPoint.Latitude = ToDegree(latDestination); 
      nextPoint.Longitude = lonOrigin; 
     } 
     if (angle == 90) 
     { 
      nextPoint.Latitude = latOrigin; 
      nextPoint.Longitude = ToDegree(lonDestination); 
     } 
     return nextPoint; 
    } 

這裏的半徑是距離。

現在的問題是當我計算短距離例如幾百公里，它完美的作品。但是，如果路程長達11,000公里，它的經度是正確的。 請不要只沿緯度或經度移動，因此其中一個在任何情況下都不會改變。在移動緯度的時候，我得到了正確的答案，但經度值並沒有更接近。 如果有不明之處，請發表評論。

Answer 1

double latDestination = lat1 + d * Math.Cos(brng); 
     double dLat = d * Math.Cos(brng); 
     double dPhi = Math.Log(Math.Tan(latDestination/2 + Math.PI/4)/Math.Tan(lat1/2 + Math.PI/4)); 
     double q = (double.IsNaN(dLat/dPhi)) ? dLat/dPhi : Math.Cos(lat1); // E-W line gives dPhi=0 
     double dLon = d * Math.Sin(brng)/q; 
     // check for some daft bugger going past the pole 
     if (Math.Abs(latDestination) > Math.PI/2) 
      latDestination = latDestination > 0 ? Math.PI - latDestination : -(Math.PI - latDestination); 

     lonDestination = (lon1 + dLon + 3 * Math.PI) % (2 * Math.PI) - Math.PI; 

需要稍作修改，上述公式工作正常。