计算c＃中两点之间的距离 [英] calculating distance between two points in c#

问题描述

我使用了这个代码，它取得了两个不同位置的经度和纬度，并计算了它们之间的距离。
我的代码是

  protected void Button1_Click（object sender，EventArgs e）
 {
 double lat1 = Convert.ToDouble（TextBox1.Text）; 
 double lon1 = Convert.ToDouble（TextBox2.Text）; 
 double lat2 = Convert.ToDouble（TextBox3.Text）; 
 double lon2 = Convert.ToDouble（TextBox4.Text）; 
 
 var rlat1 = Math.PI * lat1 / 180; 
 var rlat2 = Math.PI * lat2 / 180; 
 var rlon1 = Math.PI * lon1 / 180; 
 var rlon2 = Math.PI * lon2 / 180; 
 var theta = lon1-lon2; 
 var rtheta = Math.PI * theta / 180; 
 var dist = Math.Sign（rlat1）* Math.Sign（rlat2）+ Math.Cos（rlat1）* Math.Cos（rlat2）* Math.Cos（rtheta）; 
 dist = Math.Acos（dist）; 
 dist = dist * 180 / Math.PI; 
 dist = dist * 60 * 1.1515; 
 dist = dist * 1.609344; 
 TextBox5.Text = dist.ToString（0。######）; 
} 
  

但是对于所有输入值，我得到的结果是NaN.please help

解决方案

好吧，因为我带着你以前的回答带你走上了花园之路，我移植了

 这个给你一个算法：
 > void Main（）
 {
 double lat1 = 12.916933d，
 lon1 = 77.562658d，
 lat2 = 12.930140d，
 lon2 = 77.587732d; 
 double dist = GetDistanceFromLatLonInKm（lat1，lon1，lat2，lon2）; 
 // dist == 3.08890370651166 yay！ 
 
 
 
 double GetDistanceFromLatLonInKm（double lat1，
 double lon1，
 double lat2，
 double lon2）{
 var R = 6371d; //以公里为单位的地球半径
 var dLat = Deg2Rad（lat2  -  lat1）; // deg2rad低于
 var dLon = Deg2Rad（lon2  -  lon1）; 
 var a = 
 Math.Sin（dLat / 2d）* Math.Sin（dLat / 2d）+ 
 Math.Cos（Deg2Rad（lat1））* Math.Cos（Deg2Rad（lat2 ））* 
 Math.Sin（dLon / 2d）* Math.Sin（dLon / 2d）; 
 var c = 2d * Math.Atan2（Math.Sqrt（a），Math.Sqrt（1d  -  a））; 
 var d = R * c; //以公里为单位的距离
返回d; 
} 
 
 double Deg2Rad（double deg）{
 return deg *（Math.PI / 180d）; 
 
  

当您提供固定值时，您的计算似乎正常工作： / p>

  var lat1 = 0d; 
 var lon1 = 52d; 
 var lat2 = 0d; 
 var lon2 = -52d; 
  

这意味着这些转换失败：

  double lat1 = Convert.ToDouble（TextBox1.Text）; 
 double lon1 = Convert.ToDouble（TextBox2.Text）; 
 double lat2 = Convert.ToDouble（TextBox3.Text）; 
 double lon2 = Convert.ToDouble（TextBox4.Text）; 
  

如果仍有问题，请在这些行上放置断点并查看值 TextBox1.Text 等。

为了更加可预测地分析浮点数，最好提供文化信息：

  Convert.ToDouble（1.2，System.Globalization.CultureInfo.InvariantCulture）
  

i used this code which takes longitude and latitude of two different location and calculates the distance between them my code is

protected void Button1_Click(object sender, EventArgs e)
{
    double lat1= Convert.ToDouble(TextBox1.Text);
    double lon1= Convert.ToDouble(TextBox2.Text);
    double lat2= Convert.ToDouble(TextBox3.Text);
    double lon2= Convert.ToDouble(TextBox4.Text);

    var rlat1 = Math.PI * lat1/180;
    var rlat2 = Math.PI * lat2/180;
    var rlon1 = Math.PI * lon1/180;
    var rlon2 = Math.PI * lon2 / 180;
    var theta = lon1-lon2;
    var rtheta = Math.PI * theta/180;
    var dist = Math.Sign(rlat1) * Math.Sign(rlat2) + Math.Cos(rlat1) * Math.Cos(rlat2) * Math.Cos(rtheta);
    dist = Math.Acos(dist);
    dist = dist * 180/Math.PI;
    dist = dist * 60 * 1.1515;
    dist = dist * 1.609344 ;
    TextBox5.Text = dist.ToString("0.######");  
}

but for all the input values the result i am getting is NaN.please help me.

解决方案

Ok, because I led you up the garden path with my previous answer, I ported this to give you an algorithm that works:

void Main()
{
    double lat1=12.916933d, 
           lon1=77.562658d,
           lat2=12.930140d,
           lon2=77.587732d;
    double dist = GetDistanceFromLatLonInKm(lat1, lon1, lat2, lon2);
    // dist == 3.08890370651166 yay!

}

double GetDistanceFromLatLonInKm(double lat1,
                                 double lon1,
                                 double lat2,
                                 double lon2) {
  var R = 6371d; // Radius of the earth in km
  var dLat = Deg2Rad(lat2 - lat1);  // deg2rad below
  var dLon = Deg2Rad(lon2 - lon1); 
  var a = 
    Math.Sin(dLat / 2d) * Math.Sin(dLat / 2d) +
    Math.Cos(Deg2Rad(lat1)) * Math.Cos(Deg2Rad(lat2)) * 
    Math.Sin(dLon / 2d) * Math.Sin(dLon / 2d); 
  var c = 2d * Math.Atan2(Math.Sqrt(a), Math.Sqrt(1d - a)); 
  var d = R * c; // Distance in km
  return d;
}

double Deg2Rad(double deg) {
  return deg * (Math.PI / 180d);
}

Your calculation appears to work correctly when you supply fixed values:

var lat1 = 0d;
var lon1 = 52d;
var lat2 = 0d;
var lon2 = -52d;

which rather implies that these conversions are failing:

double lat1 = Convert.ToDouble(TextBox1.Text);
double lon1 = Convert.ToDouble(TextBox2.Text);
double lat2 = Convert.ToDouble(TextBox3.Text);
double lon2 = Convert.ToDouble(TextBox4.Text);

If you're still having trouble, place a breakpoint on these lines and take a look at the values of TextBox1.Text etc.

For more predictable parsing of floating point numbers, it's best to supply culture information:

Convert.ToDouble("1.2", System.Globalization.CultureInfo.InvariantCulture)

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