def METHOD_NAME(repositoryUrl, catalogName, catalogDirectory, beVerbose):
	# find out some pathes and init the zlib decompressor
	subdir = catalogName[0:2]
	filename = catalogName[2:] + "C"
	url = repositoryUrl + "/data/" + subdir + "/" + filename
	destDir = catalogDirectory + "/" + subdir + "/"
	dest = destDir + filename
	#decoder = zlib.decompressobj()
	# create target directory if not existing and open output file
	createDirectory(destDir)
	outputFile = open(dest, 'wb')
	# download the catalog
	try:
		f = urlopen(url)
		meta = f.info()
		fileSize = int(meta.getheaders("Content-Length")[0])
		if beVerbose:
			print "retrieving " + catalogName + " - " + str(fileSize) + " bytes"
		with open(dest, "wb") as local_file:
			local_file.write(f.read())
	except HTTPError, e:
		printError("HTTP: " + e.code + url)
	except URLError, e:
		printError("URL:" + e.reason + url)