public List<Event> relatedEvents(GeoLocation location)
{
List<Event> relatedEvents = new List<Event>();
foreach (Event e in _db.Events)
{
double distanceInKm = e.DistanceBetweenPlaces(location);
if (e.isRelevantTimeEvent()) // time of Event is relevant
{
if (distanceInKm <= e.LocationRadius)
{
relatedEvents.Add(e);
}
}
}
return relatedEvents;
}
public double DistanceBetweenPlaces(GeoLocation e2)
{
double R = 6371; // km
double sLat1 = Math.Sin(Radians(this.LocationLatitude));
double sLat2 = Math.Sin(Radians(e2.LocationLatitude));
double cLat1 = Math.Cos(Radians(this.LocationLatitude));
double cLat2 = Math.Cos(Radians(e2.LocationLatitude));
double cLon = Math.Cos(Radians(this.LocationLongitude) - Radians(e2.LocationLongitude));
double cosD = sLat1 * sLat2 + cLat1 * cLat2 * cLon;
double d = Math.Acos(cosD);
double dist = R * d;
return dist;
}
public GeoLocation MiddlePointBetweenPlaces(GeoLocation e2)
{
double dLon = Radians(e2.LocationLongitude - this.LocationLongitude);
//convert to radians
double lat1 = Radians(this.LocationLatitude);
double lat2 = Radians(e2.LocationLatitude);
double lon1 = Radians(this.LocationLongitude);
double Bx = Math.Cos(lat2) * Math.Cos(dLon);
double By = Math.Cos(lat2) * Math.Sin(dLon);
double latMid = Math.Atan2(Math.Sin(lat1) + Math.Sin(lat2), Math.Sqrt((Math.Cos(lat1) + Bx) * (Math.Cos(lat1) + Bx) + By * By));
double lonMid = lon1 + Math.Atan2(By, Math.Cos(lat1) + Bx);
return new GeoLocation(RadianToDegree(lonMid), RadianToDegree(latMid));
}