/// <summary>
/// Returns null if not found.
/// </summary>
public static Navaid Find(this MultiMap <string, Navaid> navaids,
string id, ICoordinate c, double delta = 1e-3)
{
var matches = navaids.FindAll(id);
return(matches.FirstOrDefault(x =>
Abs(c.Lat - x.Lat) <= delta && Abs(c.Lon - x.Lon) <= delta));
}
/// <summary>
/// Find all WptNeighbors by ident of a waypoint.
/// Returns an empty list if none is found.
/// </summary>
public List <int> FindAllById(string ident)
{
return(searchHelper.FindAll(ident));
}