Google Maps explicitly forbid using map tiles offline or caching them, but I think Microsoft Bing Maps don't say anything explicitly against it, and I guess you are not planning to use your program commercially (?)
Then, you could use this. It creates a cache, first loading a tile from memory, else fom disk, else from the internet, always caching everything to disk for reuse. Of course you'll have to figure out how to tweak it, specifically how to get the tile coordinates and zoom level you need, and for this I suggest strongly this site. Good study!
#!/usr/bin/env python
# coding: utf-8
import os
import Image
import random
import urllib
import cStringIO
import cairo
#from geofunctions import *
class TileServer(object):
def __init__(self):
self.imdict = {}
self.surfdict = {}
self.layers = 'ROADMAP'
self.path = './'
self.urltemplate = 'http://ecn.t{4}.tiles.virtualearth.net/tiles/{3}{5}?g=0'
self.layerdict = {'SATELLITE': 'a', 'HYBRID': 'h', 'ROADMAP': 'r'}
def tiletoquadkey(self, xi, yi, z):
quadKey = ''
for i in range(z, 0, -1):
digit = 0
mask = 1 << (i - 1)
if(xi & mask) != 0:
digit += 1
if(yi & mask) != 0:
digit += 2
quadKey += str(digit)
return quadKey
def loadimage(self, fullname, tilekey):
im = Image.open(fullname)
self.imdict[tilekey] = im
return self.imdict[tilekey]
def tile_as_image(self, xi, yi, zoom):
tilekey = (xi, yi, zoom)
result = None
try:
result = self.imdict[tilekey]
except:
filename = '{}_{}_{}_{}.jpg'.format(zoom, xi, yi, self.layerdict[self.layers])
fullname = self.path + filename
try:
result = self.loadimage(fullname, tilekey)
except:
server = random.choice(range(1,4))
quadkey = self.tiletoquadkey(*tilekey)
print quadkey
url = self.urltemplate.format(xi, yi, zoom, self.layerdict[self.layers], server, quadkey)
print "Downloading tile %s to local cache." % filename
urllib.urlretrieve(url, fullname)
result = self.loadimage(fullname, tilekey)
return result
if __name__ == "__main__":
ts = TileServer()
im = ts.tile_as_image(5, 9, 4)
im.show()
