/// <summary>
/// Returns the distance (in metres) between two geospatial points defined
/// by their longitude and latitude.
/// </summary>
/// <param name="u"></param>
/// <param name="v"></param>
/// <returns></returns>
public static float Haversine(IGeospatial u, IGeospatial v)
{
var R = 6371e3; // Earth radius in metres
var lat = DegreesToRadians(v.Latitude - u.Latitude);
var lng = DegreesToRadians(v.Longitude - u.Longitude);
var h1 = Math.Sin(lat / 2) * Math.Sin(lat / 2) +
Math.Cos(DegreesToRadians(u.Latitude)) * Math.Cos(DegreesToRadians(v.Latitude)) *
Math.Sin(lng / 2) * Math.Sin(lng / 2);
var h2 = 2 * Math.Asin(Math.Min(1, Math.Sqrt(h1)));
return((float)(R * h2));
}
public static double GetDistanceInMiles(this IGeospatial from, IGeospatial to)
{
// Based on https://www.geodatasource.com/developers/c-sharp
double theta = from.Longitude - to.Longitude;
double dist =
Math.Sin(from.Latitude.ConvertDegreesToRadians()) * Math.Sin(to.Latitude.ConvertDegreesToRadians()) +
Math.Cos(from.Latitude.ConvertDegreesToRadians()) * Math.Cos(to.Latitude.ConvertDegreesToRadians()) *
Math.Cos(theta.ConvertDegreesToRadians());
dist = Math.Acos(dist).ConvertRadiansToDegrees();
dist = dist * 60 * 1.1515;
return(dist);
}
