public void Addto(GeoLocation point)
{
data_list.Add(point);
}
/// <summary>
/// Calculates the intersection point3 in degrees from point1, crs13, point2, crs23
/// </summary>
/// <param name="point1_deg"></param>
/// <param name="crs13_radians"></param>
/// <param name="point2_deg"></param>
/// <param name="crs23_radians"></param>
/// <returns></returns>
public static GeoLocation GetIntersection(GeoLocation point1_deg, double crs13_radians, GeoLocation point2_deg, double crs23_radians)
{
double lat1 = DegreesToRadians(point1_deg.Latitude);
double lon1 = DegreesToRadians(point1_deg.Longitude);
double lat2 = DegreesToRadians(point2_deg.Latitude);
double lon2 = DegreesToRadians(point2_deg.Longitude);
double crs12, crs21, ang1, ang2, ang3, dst13, lat3, lon3, dlon;
GeoLocation point3 = new GeoLocation();
double delta_lat = lat2 - lat1;
double delta_lon = lon2 - lon1;
//double dst12 = 2 * Math.Asin(Math.Pow(Math.Sqrt(Math.Sin((lat1 - lat2) / 2),2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Pow(Math.Sin((lon1 - lon2) / 2),2)));
double dst12 = 2 * Math.Asin(Math.Sqrt(Math.Sin(delta_lat / 2) * Math.Sin(delta_lat / 2) + Math.Cos(lat1) * Math.Cos(lat2) * Math.Sin(delta_lon / 2) * Math.Sin(delta_lon / 2)));
double dist12 = geolib.RadiansToDegrees(dst12) * 60 * 1.1515 * 0.8684;
// Debug.WriteLine("dst12: " + dist12, "GetIntersection");
double ang_a = Math.Acos((Math.Sin(lat2) - Math.Sin(lat1) * Math.Cos(dst12)) / (Math.Sin(dst12) * Math.Cos(lat1)));
double ang_b = Math.Acos((Math.Sin(lat1) - Math.Sin(lat2) * Math.Cos(dst12)) / (Math.Sin(dst12) * Math.Cos(lat2)));
if (Math.Sin(lon2 - lon1) > 0)
{
crs12 = ang_a;
crs21 = 2 * Math.PI - ang_b;
}
else
{
crs12 = 2 * Math.PI - ang_a;
crs21 = ang_b;
}
ang1 = d_mod(crs13_radians - crs12 + Math.PI, 2 * Math.PI) - Math.PI;
ang2 = d_mod(crs21 - crs23_radians + Math.PI, 2 * Math.PI) - Math.PI;
//Debug.WriteLine("Angle2-1-3: " + geolib.RadiansToDegrees(ang1) + " Angle1-2-3: " + geolib.RadiansToDegrees(ang2), "GetIntersection");
if (Math.Sin(ang1) == 0 && Math.Sin(ang2) == 0)
{
//"infinity of intersections"
Debug.WriteLine("ERROR: infinity of intersections found.", "GetIntersection");
point3.Latitude = 99; //return an invalid degree to signal failure - which means lines are parallel
return(point3);
}
else if ((Math.Sin(ang1) * Math.Sin(ang2)) < 0)
{
//"intersection ambiguous"
Debug.WriteLine("ERROR: intersection ambiguous found.", "GetIntersection");
point3.Latitude = 99; //return an invalid degree to signal failure - which means lines are parallel
return(point3);
}
else
{
ang1 = Math.Abs(ang1);
ang2 = Math.Abs(ang2);
ang3 = Math.Acos(-Math.Cos(ang1) * Math.Cos(ang2) + Math.Sin(ang1) * Math.Sin(ang2) * Math.Cos(dst12));
dst13 = Math.Atan2(Math.Sin(dst12) * Math.Sin(ang1) * Math.Sin(ang2), Math.Cos(ang2) + Math.Cos(ang1) * Math.Cos(ang3));
lat3 = Math.Asin(Math.Sin(lat1) * Math.Cos(dst13) + Math.Cos(lat1) * Math.Sin(dst13) * Math.Cos(crs13_radians));
dlon = Math.Atan2(Math.Sin(crs13_radians) * Math.Sin(dst13) * Math.Cos(lat1), Math.Cos(dst13) - Math.Sin(lat1) * Math.Sin(lat3));
lon3 = d_mod(lon1 + dlon + Math.PI, 2 * Math.PI) - Math.PI;
point3.Latitude = RadiansToDegrees(lat3);
point3.Longitude = RadiansToDegrees(lon3);
//Debug.WriteLine("Lat: " + point3.Latitude + " Lon: " + point3.Longitude, "GetIntersection");
return(point3);
}
}
