C# 计算两坐标之间的距离(米)【默认北半球，东半球】 经纬度

计算距离核心代码：

//private const double EARTH_RADIUS = 6378.137; //赤道半径 -地球半径
//private const double EARTH_RADIUS = 6356.755; //极半径    -地球半径
private const double EARTH_RADIUS = 6371.004;    //平均半径 -地球半径

/// <summary>
/// 度数转弧度
/// </summary>
/// <param name="d">度数</param>
/// <returns></returns>
private static double rad(double d)
{
    return d * Math.PI / 180.0;
}

/// <summary>
/// 计算坐标距离:默认北半球(N)纬度为正，南半球(S)为负；东半球(E)经度为正，西半球(W)为负
/// </summary>
/// <param name="lat1">坐标A纬度</param>
/// <param name="lng1">坐标A经度度</param>
/// <param name="lat2">坐标B纬度</param>
/// <param name="lng2">坐标B经度</param>
/// <returns></returns>
public double GetDistance(double lat1, double lng1, double lat2, double lng2)
{
    double radLat1 = rad(lat1);
    double radLat2 = rad(lat2);
    double a = radLat1 - radLat2;
    double b = rad(lng1) - rad(lng2);

    double s = 2 * Math.Asin(Math.Sqrt(Math.Pow(Math.Sin(a / 2), 2) +
     Math.Cos(radLat1) * Math.Cos(radLat2) * Math.Pow(Math.Sin(b / 2), 2)));
    s = s * EARTH_RADIUS;
    s = Math.Round(s * 10000) / 10000;
    return s;
}

业务场景：

/// <summary>
/// 计算两坐标之间的距离(米)【默认北半球，东半球】
/// </summary>
/// <param name="input"></param>
/// <returns></returns>public double CalculateDistance(CalculateDistanceRequestDto input)
{
    double distance = 0;
    /*基本思路：
     *      设第一点A的经 纬度为(LonA, LatA)，第二点B的经纬度为(LonB, LatB)，
     *      按照0度经线的基准，东经取经度的正值(Longitude)，西经取经度负值(-Longitude)，
     *      北纬取90-纬度值(90- Latitude)，南纬取90+纬度值(90+Latitude)，
     *      则经过上述处理过后的两点被计为(MLonA, MLatA)和(MLonB, MLatB)。
     *      那么根据三角推导，可以得到计算两点距离的如下公式：
     *      C = sin(MLatA)*sin(MLatB)*cos(MLonA-MLonB) + cos(MLatA)*cos(MLatB)
     *      Distance = R*Arccos(C)*Pi/180 
     * **/
    //根据输入坐标，调整
    var simpleCoords1 = GetSimpleCoords(input.Coords1);
    var simpleCoords2 = GetSimpleCoords(input.Coords2);
    var distance = GetDistance(simpleCoords1.lat, simpleCoords1.lon, simpleCoords2.lat, simpleCoords2.lon) * 1000;//单位：米    
    return distance;
}
//坐标归化
private BuoyDataCoordsSimpleDto GetSimpleCoords(BuoyDataCoordsDto coords)
{
    BuoyDataCoordsSimpleDto retData = new BuoyDataCoordsSimpleDto();
    //默认北纬，东经
    //纬度
    if (coords.NS.ToUpper() == "S")
    {
        retData.lat = -coords.lat;      
    }
    else
    {
        retData.lat = coords.lat;       
    }
    //经度
    if (coords.EW.ToUpper() == "W")
    {
        retData.lon = -coords.lon;
    }
    else
    {
        retData.lon = coords.lon;
    }
    return retData;
}

其中的参数实体

/// <summary>
/// 计算距离坐标实体
/// </summary>
public class CalculateDistanceRequestDto 
{        
    /// <summary>
    /// 坐标1
    /// </summary>        
    public CoordsDto Coords1 { get; set; }

    /// <summary>
    /// 坐标2
    /// </summary>        
    public CoordsDto Coords2 { get; set; }
}

/// <summary>
/// 坐标信息实体
/// </summary>
public class CoordsDto
{        
    /// <summary>
    /// 纬度
    /// </summary>        
    public double lat { get; set; }

    /// <summary>
    /// 南纬北纬
    /// </summary>        
    public string NS { get; set; }

    /// <summary>
    /// 经度
    /// </summary>        
    public double lon { get; set; }

    /// <summary>
    /// 东经西经
    /// </summary>        
    public string EW { get; set; }
}