Convert a distance in to an angle along a great circle.

    Args:
        distance (float): Distance to convert to degrees
        units (str): Unit type to be used for distances

    Returns:
        float: Angle in degrees

    Raises:
        ValueError: Unknown value for ``units``

def distance_to_angle(distance, units='metric'):
    """Convert a distance in to an angle along a great circle.

    Args:
        distance (float): Distance to convert to degrees
        units (str): Unit type to be used for distances

    Returns:
        float: Angle in degrees

    Raises:
        ValueError: Unknown value for ``units``
    """
    if units in ('km', 'metric'):
        pass
    elif units in ('sm', 'imperial', 'US customary'):
        distance *= STATUTE_MILE
    elif units in ('nm', 'nautical'):
        distance *= NAUTICAL_MILE
    else:
        raise ValueError('Unknown units type %r' % units)

    return math.degrees(distance / BODY_RADIUS)