def split_bounds(minx, miny, maxx, maxy):
	"""
	Splits the bounding box in half across it's shortest dimension
	"""
	if maxy - miny > maxx - minx:
		midy = (miny + maxy) / 2
		return [(minx, miny, maxx, midy), (minx, midy, maxx, maxy)]
	else:
		midx = (minx + maxx) / 2
		return [(minx, miny, midx, maxy), (midx, miny, maxx, maxy)]