/// <summary>
/// 根据已经点、方位和角度，计算另一点坐标。
/// </summary>
/// <param name="angle">航线角(磁方向，弧度单位)</param>
/// <param name="distance">距离(公里)</param>
/// <param name="point">参考点</param>
/// <returns></returns>
public static PointCoordinate CalcuateCoordinate(PointCoordinate point, double angle,
double distance)
{
PointCoordinate p = new PointCoordinate();
double R = 6371.0; // earth's mean radius in km
double d = distance / R;
double lat1 = GreatCircleArgorithm.ConvertToARC(GreatCircleArgorithm.ConvertToDeg(point.Latitide));
double lon1 = GreatCircleArgorithm.ConvertToARC(GreatCircleArgorithm.ConvertToDeg(point.Longitude));
double brng = GreatCircleArgorithm.ConvertToDeg(angle) * Math.PI / 180; //将度转换为弧度
double lat2 = lat1 + d * Math.Cos(brng);
double dLat = lat2 - lat1;
double dPhi = Math.Log(Math.Tan(lat2 / 2 + Math.PI / 4) / Math.Tan(lat1 / 2 + Math.PI / 4));
double q = (Math.Abs(dLat) > 0.000000001) ? dLat / dPhi : Math.Cos(lat1);
double dlon = d * Math.Sin(brng) / q;
if (Math.Abs(lat2) > Math.PI / 2)
{
lat2 = lat2 > 0 ? Math.PI - lat2 : -Math.PI - lat2;
}
double lon2 = (lon1 + dlon + Math.PI) % (2 * Math.PI) - Math.PI;
p.Latitide = GreatCircleArgorithm.ConvertToDMS(GreatCircleArgorithm.ConvertToDegree(lat2));
p.Longitude = GreatCircleArgorithm.ConvertToDMS(GreatCircleArgorithm.ConvertToDegree(lon2));
return(p);
}
/// <summary>
/// 计算两点的角度。
/// </summary>
/// <param name="firstPoint"></param>
/// <param name="endPoint"></param>
/// <returns>返回60进制的度分秒角度 </returns>
public static double CalculateAngle(PointCoordinate firstPoint, PointCoordinate endPoint)
{
double lat2 = GreatCircleArgorithm.ConvertToDeg(endPoint.Latitide);
double lon2 = GreatCircleArgorithm.ConvertToDeg(endPoint.Longitude);
double lat1 = GreatCircleArgorithm.ConvertToDeg(firstPoint.Latitide);
double lon1 = GreatCircleArgorithm.ConvertToDeg(firstPoint.Longitude);
double dLon = GreatCircleArgorithm.ConvertToARC((lon2 - lon1));
double dPhi = Math.Log(Math.Tan(GreatCircleArgorithm.ConvertToARC(lat2) / 2 + Math.PI / 4) / Math.Tan(GreatCircleArgorithm.ConvertToARC(lat1) / 2 + Math.PI / 4));
if (Math.Abs(dLon) > Math.PI)
{
dLon = dLon > 0 ? -(2 * Math.PI - dLon) : (2 * Math.PI + dLon);
}
double angle = Math.Atan2(dLon, dPhi);
return(GreatCircleArgorithm.ConvertToDMS((GreatCircleArgorithm.ConvertToDegree(angle) + 360) % 360));
}
/// <summary>
/// 计算两点间距离。
/// see http://williams.best.vwh.net/avform.htm#Rhumb
/// </summary>
/// <param name="firstPoint"></param>
/// <param name="endPoint"></param>
/// <returns></returns>
public static double CalculateDistance(PointCoordinate firstPoint, PointCoordinate endPoint)
{
double R = 6371;
double lat2 = GreatCircleArgorithm.ConvertToDeg(endPoint.Latitide);
double lon2 = GreatCircleArgorithm.ConvertToDeg(endPoint.Longitude);
double lat1 = GreatCircleArgorithm.ConvertToDeg(firstPoint.Latitide);
double lon1 = GreatCircleArgorithm.ConvertToDeg(firstPoint.Longitude);
double dLat = GreatCircleArgorithm.ConvertToARC(lat2 - lat1);
double dLon = Math.Abs(GreatCircleArgorithm.ConvertToARC(lon2 - lon1));
double dPhi = Math.Log(Math.Tan(GreatCircleArgorithm.ConvertToARC(lat2) / 2 + Math.PI / 4) / Math.Tan(GreatCircleArgorithm.ConvertToARC(lat1) / 2 + Math.PI / 4));
double q = (Math.Abs(dLat) > 0.00000001) ? dLat / dPhi : Math.Cos(GreatCircleArgorithm.ConvertToARC(lat1));
if (dLon > Math.PI)
{
dLon = 2 * Math.PI - dLon;
}
double d = Math.Sqrt(dLat * dLat + q * q * dLon * dLon);
return(d * R);
}
