基于B/S结构的地图切片前端预存储技术

Front-end pre-stored technology of map tiles based on B/S

目前,主流的客户端缓存地图切片技术都是基于C/S结构,这种技术在移动设备的地图APP程序中应用较广泛。B/S结构由于安全机制的限制,不能够在客户端存储大容量的文件,这一特点严重阻碍了基于Web GIS技术的地图应用程序的发展。最新的HTML5文件系统API技术能够实现在客户端存储大批量文件,可以将海量地图切片缓存到用户的电脑硬盘或者移动设备中,在需要访问地图时从客户端调出使用。基于该功能,用户在B/S结构下将地图切片缓存到客户端,在离线环境中浏览预先存储好的地图数据,缩短系统的响应时间,改善用户体验。

At present, the mainstream of map tiles on client is based on C/S structure. This technique is widely used in mobile equipment for map in APP program. However, the B/S structure because of security restrictions cannot be on the client to store large amounts of data. This characteristic has seriously hindered the development of Web GIS technology application based on map. The latest file system API technology of HTML5 can store large quantities of documents on the client. With this technology we can store lots of map tiles to the hard disk of user＇s computer or a mobile device. With this method, users can browse good maps based on B/S structure at off-line environment. It can shorten the time of system response, improving the user experience.