python geohash

gistfile1.py

geoHashCharMap = ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9',
                  'b', 'c', 'd', 'e', 'f', 'g', 'h', 'j', 'k', 'm',
                  'n', 'p', 'q', 'r', 's', 't', 'u', 'v', 'w', 'x',
                  'y', 'z']

stdCharMap = [chr(ord('0') + i) for i in range(10)] + [chr(ord('A') + i) for i in range(26)]

geoHashCharToStdCharMap = dict(zip(geoHashCharMap, stdCharMap))

def geoHashToBin(geoHash):
    return [bin(int(geoHashCharToStdCharMap[c], 32))[2:].rjust(5, '0')
            for c in geoHash]

def geoHashBinToLatLonBin(geoHashBin):
    return (''.join(geoHashBin)[1::2], ''.join(geoHashBin)[::2]) 

def latLonBinToLatLon(latLonBin):
    latBinStr, lonBinStr = latLonBin
    latBinInt, lonBinInt = int(latBinStr, 2), int(lonBinStr, 2)
    
    return (latBinInt/float(2**len(latBinStr)) * 180.0 - 90,
            lonBinInt/float(2**len(lonBinStr)) * 360.0 - 180.0)

            
def geoHashToLatLon(geoHash):
    return latLonBinToLatLon(geoHashBinToLatLonBin(geoHashToBin(geoHash)))