/// <summary>
/// 计算坐标距离
/// </summary>
/// <param name="lngA">坐标A经度</param>
/// <param name="latA">坐标A纬度</param>
/// <param name="lngB">坐标B经度</param>
/// <param name="latB">坐标B纬度</param>
/// <returns></returns>
private double AccountDistance(double lngA, double latA, double lngB, double latB)
{
double DistanceLng = 102834.74258026089786013677476285;
double DistanceLat = 111712.69150641055729984301412873;
double LngAbs = Math.Abs((lngA - lngB) * DistanceLng);
double LatAbs = Math.Abs((latA - latB) * DistanceLat);
return Math.Sqrt((LatAbs * LatAbs + LngAbs * LngAbs));
}