def greatcircle_to_greatcircle(from_greatcircle_coord, to_greatcircle_frame):
    """Transform between two greatcircle frames."""
    intermediate_from = from_greatcircle_coord.transform_to(
        from_greatcircle_coord.pole)
    intermediate_to = intermediate_from.transform_to(to_greatcircle_frame.pole)
    return intermediate_to.transform_to(to_greatcircle_frame)
