routing-functions-non-classic.md

copyright	lastupdated	subcollection
years 2017, 2020	2020-01-08	AnalyticsEngine

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Routing functions

{: #routing-functions}

The spatio-temporal library includes routing functions that list the edges that yield a path from one node to another node.

To show you how to use the routing functions in the spatio-temporal library, the code samples in this topic use the OSM map for the city of Atlanta downloaded from OpenStreetMap.

To calculate a route:

1. Create a router and read from the OSM map:

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

2. Set the start and end points:

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

3. Find the best route with the minimal time cost (the fastest route timewise):

   >>> 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. Find the best route with minimal distance cost (the fastest route distance-wise):

   >>> 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)]