gistfile1.txt

#!/usr/bin/python

import sys
import png
from pprint import pprint

cx = 0
width = 4000
height = 4000
image = [ [ 0 for y in range ( width )  ] for x in range( height ) ]

bitdepth = 2
maxval = pow(2, bitdepth)

delta_lng = .8 
delta_lat = delta_lng

lng_low = -118.8
lng_high = lng_low + delta_lng

lat_low = 33.70
lat_high = lat_low + delta_lat

mult_lng = 360 / delta_lng * .999
mult_lat = 180 / delta_lat * .999

for line in sys.stdin:
  lat, lng = line.split(',')
  lat = float(lat)
  lng = float(lng)
  cx += 1
  if(lng > lng_low and lng < lng_high and lat > lat_low and lat < lat_high):
    x = int(round( (mult_lng * width/360.0) * (lng - lng_low)))
    y = int(round( (mult_lat * height/180.0) * (lat - lat_low)))
    try:
      if image[y][x] < maxval:
        image[y][x] += 1

    except Exception as ex:
      print(x, y)
      raise ex 

f = sys.stdout
w = png.Writer(width, height, greyscale=True, bitdepth=bitdepth)
w.write(f, reversed(image))
f.close()