def level_dic():
    """
    http://wiki.openstreetmap.org/wiki/Zoom_levels
    """
    data = {(0): 360.0, (1): 180.0, (2): 90.0, (3): 45.0, (4): 22.5, (5): 
        11.25, (6): 5.625, (7): 2.813, (8): 1.406, (9): 0.703, (10): 0.352,
        (11): 0.176, (12): 0.088, (13): 0.044, (14): 0.022, (15): 0.011, (
        16): 0.005, (17): 0.003, (18): 0.001, (19): 0.0005}
    return data
