/// <summary>
/// 计算距离，如返回最大值需要检查数据
/// </summary>
public static double GetDistanceInKm(GeoInfo startPoint, GeoInfo endPoint, double?defaultValue)
{
if (!IsGeoValid(startPoint) || !IsGeoValid(endPoint))
{
return(defaultValue ?? throw new Exception("无法计算距离，传入坐标错误"));
}
var startlatrad = Rad(startPoint.Lat);
var endlatrad = Rad(endPoint.Lat);
var a = startlatrad - endlatrad;
var b = Rad(startPoint.Lon - endPoint.Lon);
return(2 * EARTH_RADIUS * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) +
Math.Cos(startlatrad) *
Math.Cos(endlatrad) *
Math.Pow(Math.Sin(b / 2), 2))));
}
/// <summary> /// 验证经纬度数值正确性 /// </summary> private static bool IsGeoValid(GeoInfo point) => point != null && Math.Abs(point.Lat) <= 90 && Math.Abs(point.Lon) <= 180;
