地图相关知识

Google 地图切片URL地址解析 :http://blog.youkuaiyun.com/mygisforum/article/details/7582449

腾讯与百度地图瓦片规则分析:点击打开链接

墨卡托投影:

http://blog.youkuaiyun.com/mygisforum/article/details/13295223

https://developers.google.com/maps/documentation/javascript/v2/overlays?hl=zh-CN#Google_Maps_Coordinates