GoogleMap和高德地图最新的瓦片图地址是用什么加密或者压缩

https://mts1.googleapis.com/vt?pb=!1m4!1m3!1i13!2i2475!3i3029!2m3!1e0!2sm!3i293208756!3m9!2sen-US!3sUS!5e18!12m1!1e47!12m3!1e37!2m1!1ssmartmaps!4e0!5m1!5f2

http://mt0.google.cn/vt/pb=!1m5!1m4!1i{z}!2i{x}!3i{y}!4i128!2m2!1e0!3i333048300!3m7!2szh-CN!3scn!5e1105!12m1!1e47!12m1!1e3!4e0

瓦片大小128

url: 'http://mt{0-3}.google.cn/maps/vt/pb=!1m4!1m3!1i{z}!2i{x}!3i{y}!2m3!1e0!2sm!3i376063156!3m8!2szh-CN!3scn!5e1105!12m4!1e68!2m2!1sset!2sRoadmap!4e0!5m1!1e0',

瓦片大小256