code: @Pure
  	public double distance(double x, double y) {
  		if (isValidPrimitive()) {
  			final GeoLocationPoint p = getGeoPosition();
  			return Point2D.getDistancePointPoint(p.getX(), p.getY(), x, y);
  		}
  		return Double.NaN;
  	}
docs: Replies the distance between the given point and this bus stop.
  
  @param x x coordinate.
  @param y y coordinate.
  @return the distance to this bus stop