Linked Connections

Launching http://linkedconnections.org - a new publishing mechanism for scalable route planning advice using the Web's principles (hypermedia, REST, linked data)

Ever since public transit agencies have found their way to the Web, they inform travelers using route planning software made available on their website. These travelers also need to be informed about other modes of transport, for which they have to consult other websites, or for which they have to ask the transit agency’s server maintainer to implement new functionalities.

Figure: Simplified illustration the Linked Connections publishing method
With Linked Connections, we introduce an affordable publishing method for transit data, which allows user agents to execute the route planning algorithm. We publish paged documents containing a stream of hops between transit stops (connections, blue squares) sorted by departure time. Using these documents, clients are able to perform intermodal route planning in a reasonable time. Furthermore, such clients are fully in charge of the algorithm, and can now also route in different ways by integrating datasets of a user’s choice.

Transcript

1. pieter.colpaert@ugent.be http://linkedconnections.org Scalable intermodal route planning advice
2. pieter.colpaert@ugent.be http://linkedconnections.org How do you get to work?
3. pieter.colpaert@ugent.be http://linkedconnections.org Path that makes you the happiest? by @danielequercia Did you calculate the shortest path?
4. pieter.colpaert@ugent.be http://linkedconnections.org Route planners need an incredible amount of data, from different sources crossing boundaries, transport modes, etc.
5. pieter.colpaert@ugent.be http://linkedconnections.org http://api.{myapp}/?from={A}&to={B} Let’s design a web-service e.g., a plain old HTTP+JSON API
6. pieter.colpaert@ugent.be http://linkedconnections.org http://api.{myapp}/?from={A}&to={B} &departuretime=2015-09-09T14:45Z &wheelchairaccessible=true &transit_modes=plane,railway,bus,car &algoritm_mode=shortest ... Server performs the algorithm And needs to handle any request possible
7. pieter.colpaert@ugent.be http://linkedconnections.org Can we fix this problem by following the Web’s principles? - REST for scalability and high availability - Hypermedia for enabling intelligent agents - Linked Data for semantic interoperability
8. pieter.colpaert@ugent.be http://linkedconnections.org Can we decouple data publishing from the execution of the algorithm?
9. pieter.colpaert@ugent.be http://linkedconnections.org Let’s take a look at the data a connection departureTime + departureStop arrivalTime + arrivalStop another connection departureTime + departureStop arrivalTime + arrivalStop
10. pieter.colpaert@ugent.be http://linkedconnections.org time * The Connection Scan Algorithm (CSA) And this is the algorithm* ~ creating a minimum spanning tree through a sorted directed acyclic graph Squares are connections
11. pieter.colpaert@ugent.be http://linkedconnections.org Resource X Resource ... Resource 2 Resource 1 time nextPage nextPage When published in pages on the Web, route planning will need X requests instead of 1
12. pieter.colpaert@ugent.be http://linkedconnections.org Try it yourself at http://LinkedConnections.org
13. pieter.colpaert@ugent.be http://linkedconnections.org How do transfers work? A problem we can solve with Linked Data Connection A departureTime T1 departureStop S1 arrivalTime T2 arrivalStop S2 Rail Station S2 longitude X1 latitude Y1 name ... ParentStation Station S3 As S2 becomes reachable, others stops become reachable as well: nearby Bus Stop S4 Bus Stop S5 ... has parent stop
14. pieter.colpaert@ugent.be http://linkedconnections.org And multimodal route planning? Merge different connection streams over the Web of data
15. pieter.colpaert@ugent.be http://linkedconnections.org The Linked Data Fragments axis for transport Data dumps Linked Connections Answer any question on the server Route planning algorithms as a service Data publishing Data services http://api.{myapp}/?from={A}&to={B} http://{myhost}/{datafragmentid}