C# distance between two points (c# ile mesafe hesaplama)

Distance.cs

// @yasinkuyu
// 27/04/2014
 
public static double Distance(double lat1, double lon1, double lat2, double lon2, char unit)
{
    
    Func<double, double> deg2Rad = (x) => (x * (Math.PI / 180));
    Func<double, double> rad2Deg = (x) => (x / Math.PI * 180.0);
 
    var theta = lon1 - lon2;
    var dist = Math.Sin(deg2Rad(lat1)) * Math.Sin(deg2Rad(lat2)) + Math.Cos(deg2Rad(lat1)) * Math.Cos(deg2Rad(lat2)) * Math.Cos(deg2Rad(theta));
    
    dist = Math.Acos(dist);
    dist = rad2Deg(dist);
    dist = dist * 60 * 1.1515;
    
    switch (unit)
    {
        case 'K':
            dist = dist * 1.609344;
            break;
        case 'N':
            dist = dist * 0.8684;
            break;
    }
    return (dist);
}
 
Sample
Response.Write(Distance(32.9697, -96.80322, 29.46786, -98.53506, 'M') + " Miles<br>");
Response.Write(Distance(32.9697, -96.80322, 29.46786, -98.53506, 'K') + " Kilometers<br>");
Response.Write(Distance(32.9697, -96.80322, 29.46786, -98.53506, 'N') + " Nautical Miles<br>");
 
//Output
//262,677793805435 Miles
//422,738931394014 Kilometers
//228,10939614064 Nautical Miles