def polygon_scale(polygon):
    """
    For a Polygon object, return the diagonal length of the AABB.

    Parameters
    ------------
    polygon: shapely.geometry.Polygon object

    Returns
    ------------
    scale: float, length of AABB diagonal
    """
    extents = np.reshape(polygon.bounds, (2, 2)).ptp(axis=0)
    scale = (extents ** 2).sum() ** .5

    return scale