判断百度某一经纬度的地图颜色值python

from PIL import Image
import MySQLdb
import os
import urllib
import time
from multiprocessing.dummy import Pool as ThreadPool 

def gaidu_is_water((latitude,longitude)):
    while True:
        try:
            ll = longitude + ',' + latitude
            url = "http://api.map.baidu.com/staticimage?center="+ll+"&zoom=18&width=1&height=1"
            data = urllib.urlretrieve(url, ll)
            im = Image.open(ll)
            rgb_im = im.convert('RGB')
            print rgb_im.getpixel((0, 0))
            if rgb_im.getpixel((0, 0)) in [(167, 192, 224),(104, 137, 167),(153, 183, 219)]:
                # print 'is water'
                flag = 1
            else:
                flag = 0
                # print 'not water'
            # print ll,'ok'
            break
        except Exception, e:
            print e
            time.sleep(5)
            continue

if __name__ == '__main__':
    print gaidu_is_water('114.24419,22.332689')
    pool = ThreadPool(20)
    results = pool.map(gaidu_is_water, lls)
    pool.close() 
    pool.join()