| 摘要 |
A web server receives a request from a client specifying a location and a bounding area. A mapping engine creates a tile grid centered at the specified location. A seed tile is created, including or adjacent to the center location. The web server creates a resource identifier for each tile in the tile grid, and returns the tile grid including the resource identifiers to the client. The resource identifier for each tile includes the location of the seed tile and a position offset for the tile relative to the seed tile, in one embodiment specified in units of northward and eastward movement. The client requests tiles from the system using the resource identifiers previously provided by the system. Upon receiving the request, the mapping engine dynamically renders each requested tile using map data from the map database, and the web server returns the dynamically-generated tiles to the requesting client. |
