寻径函数

时空库提供有寻径函数，用于列出产生节点间路径的边缘。

为了说明如何使用时空库中的路由功能，本主题中的代码样本使用从 OpenStreetMap 下载的亚特兰大城市的 OSM 地图。

要计算路径，请完成下列步骤：

1. 创建寻径程序，并从 OSM 地图读取：

   >>> router = stc.router()
   >>> router.read_map('atlanta.osm')
   Creating Road Network...
   Road Network Created...
   Creating Network Searcher...
   Network Searcher Created...
   

2. 设置开始点和结束点：

   >>> start = stc.point(33.763261, -84.394897)
   >>> end = stc.point(33.753900, -84.385121)
   

3. 寻找时间成本最低的最佳路径（在时间方面最快的路径）：

   >>> best_time_route = router.compute_route(start, end, method='time')
   # Check time cost, in the unit of hours
   >>> best_time_route.cost
   0,044188548756240675
   # Check route path (only showing the first three points), which is a list of points in 3-tuple (osm_point_id, lat, lon)
   >>> best_time_route.path[:3]
   [(2036943312, 33.7631862, -84.3939405),
    (3523447568, 33.7632666, -84.3939315),
    (2036943524, 33.7633273, -84.3939155)]
   

4. 寻找距离成本最低的最佳路径（在距离方面最快的路径）：

   >>> best_distance_route = router.compute_route(start, end, method='distance')
   # Check distance cost, in the unit of meters
   >>> best_distance_route.cost
   2042,4082601271236
   # Check route path (only showing the first three points), which is a list of points in 3-tuple (osm_point_id, lat, lon)
   >>> best_distance_route.path[:3]
   [(2036943312, 33.7631862, -84.3939405),
    (3523447568, 33.7632666, -84.3939315),
    (2036943524, 33.7633273, -84.3939155)]