def get_center_and_radius(points):
    """
    Calculate bounding box of points in polyline and return center and diameter of fitting circle
    :param points: Points in the polyline
    :return: center of circle (x,y) and radius
    """
    x_coordinates, y_coordinates = zip(*points)

    x_min = min(x_coordinates)
    x_max = max(x_coordinates)
    y_min = min(y_coordinates)
    y_max = max(y_coordinates)

    x_diff = (x_max - x_min) / 2
    y_diff = (y_max - y_min) / 2

    return (x_min + x_diff, y_min + y_diff), y_diff