public boolean equal_at_start(PlaPointInt p_point){
  if (p_point == null)   return false;
  PlaPoint first=corner_first();
  return first.equals(p_point);
}

public boolean equal_at_start ( PlaPointInt p_point ) { if ( p_point == null ) return false ; PlaPoint first = corner_first ( ) ; return first . equals ( p_point ) ; }
returns true of the given point is equal at start of polyline
