def split_polygon(polygon):
    """Split polygon array to string.

    :param polygon: list of array describing polygon area e.g.
    '[[28.01513671875,-25.77516058680343],[28.855590820312504,-25.567220388070023],
    [29.168701171875004,-26.34265280938059]]
    :type polygon: list

    :returns: A string of polygon e.g. 50.7 7.1 50.7 7.12 50.71 7.11
    :rtype: str
    """

    if len(polygon) < 3:
        raise ValueError(
                'At least 3 lat/lon float value pairs must be provided')

    polygon_string = ''

    for poly in polygon:
        polygon_string += ' '.join(map(str, poly))
        polygon_string += ' '

    return polygon_string.strip()