A modulus-based 2D coordinate normalizer.

gistfile1.py

coords = (
    (41.2863,-73.78689),        
    (41.2864,-73.78690),        
    (41.2869,-73.78698),        
)

from math import floor

def gen_hash(coords):
    pro_lat = floor(coords[0]*1000.0)
    pro_lon = floor(coords[1]*1000.0)
    mod_lat = pro_lat%4.0
    mod_lon = pro_lon%4.0

    return 'SERVER_NAME#%s|%s:%s|%s' % (pro_lat,mod_lat,pro_lon,mod_lon)


assert(gen_hash(coords[0])==gen_hash(coords[1]))
assert(gen_hash(coords[0])==gen_hash(coords[2]))

Thanks! I had thought the same thing after, I should remove the first digit of pro_lat and pro_lon, right?