如何确定两组纬度/经度坐标之间的距离? [英] How can I determine the distance between two sets of latitude/longitude coordinates?

问题描述

我正在尝试写一些东西来确定纬度/经度坐标之间的距离.

I am trying to write something that will determine the distance between to sets of lat/lon coordinates.

我正在使用在此网站上找到的以下代码:

I am using the following code which I found on this site:

public static double distance (double lat1, double lon1, double lat2, double lon2) { 
    double lat1 = Convert.ToDouble(latitude);
    double lon1 = Convert.ToDouble(longitude);
    double lat2 = Convert.ToDouble(destlat);
    double lon2 = Convert.ToDouble(destlon);

    double theta = toRadians(lon1-lon2); 
    lat1 = toRadians(lat1); 
    lon1 = toRadians(lon1); 
    lat2 = toRadians(lat2); 
    lon2 = toRadians(lon2); 

    double dist = sin(lat1)*sin(lat2) + cos(lat1)*cos(lat2)*cos(theta); 
    dist = toDegrees(acos(dist)) * 60 * 1.1515 * 1.609344 * 1000; 

    return dist; 
} 

我的问题是我遇到了编译错误在当前上下文中不存在名称'toRadians'/'cos'/'sin/'toDegrees'..." 我做错了吗?

My problem is that I am running into the compile error "The name 'toRadians'/'cos'/'sin/'toDegrees' does not exist in the current context..." What am I doing wrong?

推荐答案

您可能要使用以下C#类:

You may want to use the following C# class:

public static class GeoCodeCalc
{
    public const double EarthRadiusInMiles = 3956.0;
    public const double EarthRadiusInKilometers = 6367.0;

    public static double ToRadian(double val) { return val * (Math.PI / 180); }
    public static double DiffRadian(double val1, double val2) { return ToRadian(val2) - ToRadian(val1); }

    public static double CalcDistance(double lat1, double lng1, double lat2, double lng2) 
    {
        return CalcDistance(lat1, lng1, lat2, lng2, GeoCodeCalcMeasurement.Miles);
    }

    public static double CalcDistance(double lat1, double lng1, double lat2, double lng2, GeoCodeCalcMeasurement m) 
    {
        double radius = GeoCodeCalc.EarthRadiusInMiles;

        if (m == GeoCodeCalcMeasurement.Kilometers) { radius = GeoCodeCalc.EarthRadiusInKilometers; }
        return radius * 2 * Math.Asin( Math.Min(1, Math.Sqrt( ( Math.Pow(Math.Sin((DiffRadian(lat1, lat2)) / 2.0), 2.0) + Math.Cos(ToRadian(lat1)) * Math.Cos(ToRadian(lat2)) * Math.Pow(Math.Sin((DiffRadian(lng1, lng2)) / 2.0), 2.0) ) ) ) );
    }
}

public enum GeoCodeCalcMeasurement : int
{
    Miles = 0,
    Kilometers = 1
}

用法:

// Calculate Distance in Miles
GeoCodeCalc.CalcDistance(47.8131545175277, -122.783203125, 42.0982224111897, -87.890625);

// Calculate Distance in Kilometers
GeoCodeCalc.CalcDistance(47.8131545175277, -122.783203125, 42.0982224111897, -87.890625, GeoCodeCalcMeasurement.Kilometers);

来源: Chris Pietschmann -计算C#和JavaScript中的地理编码之间的距离

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