Calculate number of tiles in a tile set

number_tiles.py

from sys import argv
from math import ceil, floor

res = float(argv[1])
number_zoom_levels = int(argv[2])
tile_size = int(argv[3])
bbox = [float(v) for v in argv[4].split(',')]
total_tiles = 0

for z in xrange(0, number_zoom_levels + 1):
	tile_dim = tile_size * res
	xmin = floor(bbox[0] / tile_dim)
	ymin = floor(bbox[1] / tile_dim)
	xmax = ceil(bbox[2] / tile_dim)
	ymax = ceil(bbox[3] / tile_dim)

	cols = (xmax - xmin + 1)
	rows = (ymax - ymin + 1)
	n_tiles = cols * rows
	total_tiles = total_tiles + n_tiles

	print '%d:\t%8.2f - %9dx%9d=%9d tiles' % (number_zoom_levels - z, res, cols, rows, n_tiles)

	res = res * 2

print 'Total number of tiles: ', total_tiles