Demo: tablet-based visualisation of transport data in Madrid using SPARQLstream

Jean-Paul Calbimonte, Alejandro Fernández Carrera, Oscar Corcho

22/10/2013

Ontology Engineering GroupFacultad de Informática, Universidad Politécnica de Madrid

jp.calbimonte@upm.es, ocorcho@fi.upm.es

ISWC 2013 SSN Workshop

Sensor Networks and the Web

2

Sensor Networks

users

applicationsdata

streams

Volume

VelocityVariety WEB

Universal Web-based access to Sensor data

EMT Bus transport in Madrid

• EMT: Public transport company in Madrid

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Waiting times

• How long do I wait for the next bus?

4

Only in a few bus stops

Have to physically go

and watch

EMT wants to be more WEB friendly

EMT Web Services

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EMT Services

Bus stops

https://servicios.emtmadrid.es:8443/geo/servicegeo.asmx

Bus waiting times

<Stop><IdStop>28</IdStop><PMV>61247</PMV><Name>P CASTELLANA-JUZGADOS</Name><PostalAdress>P de la Castellana, 187</PostalAdress><CoordinateX>-3.68972639781606</CoordinateX><CoordinateY>40.4650604583015</CoordinateY></Stop>

getStopsLine

getArriveStop<Arrives><Arrive><IdStop>30</IdStop><idLine>5</idLine><IsHead>True</IsHead><Destination>CHAMARTIN</Destination><IdBus>0000</IdBus><TimeLeftBus>0</TimeLeftBus><DistanceBus>16</DistanceBus><PositionXBus>-1</PositionXBus><PositionYBus>-1</PositionYBus><PositionTypeBus>0</PositionTypeBus></Arrive>

Ad-hoc XML model

Identifiers not web-friendly

Not ready for integration w/ other datasets

Working with EMT to define an Open Data strategy

Extracting data from EMT

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EMT Services

data as RDF

W3C SSN Ontology

Bus stops

https://servicios.emtmadrid.es:8443/geo/servicegeo.asmx

stati

c d

ata

<Stop><IdStop>28</IdStop><PMV>61247</PMV><Name>P CASTELLANA-JUZGADOS</Name><PostalAdress>P de la Castellana, 187</PostalAdress><CoordinateX>-3.68972639781606</CoordinateX><CoordinateY>40.4650604583015</CoordinateY></Stop>

users

applications

Static part (bus stops)

• Currently at:• http://linkeddata4.dia.fi.upm.es:8080/sparql• Graph:

http://emt.transporte.linkeddata.es/graph/stops

• All bus stops (query)• select distinct ?x where

{?x a <http://transporte.linkeddata.es/emt#BusStop>}

• URI:• http://transporte.linkeddata.es/emt/busstop/id/104

• (in the process of defining the URIs)• Could also be:

http://datos.emtmadrid.es/recurso/BusStop/104 or similar

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Extracting data from EMT

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EMT Services

data as RDF

W3C SSN Ontology

Bus stops

https://servicios.emtmadrid.es:8443/geo/servicegeo.asmx

Bus waiting times

stati

c d

ata

<Stop><IdStop>28</IdStop><PMV>61247</PMV><Name>P CASTELLANA-JUZGADOS</Name><PostalAdress>P de la Castellana, 187</PostalAdress><CoordinateX>-3.68972639781606</CoordinateX><CoordinateY>40.4650604583015</CoordinateY></Stop>

users

applications S

tream

ing

data

?

Transform Bus waiting times to RDF Stream?

EMT Live data streams

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EMT Services

https://servicios.emtmadrid.es:8443/geo/servicegeo.asmx

Bus waiting times

Str

eam

ing

data

Morph-streams

users applications

SPARQLStream queries

Endpoint available

• We’ll be using this server for the hands-on:

• http://linkeddata2.dia.fi.upm.es:9000

• The instructions of a demo are on the github wiki:• https://github.com/jpcik/morph-web/wiki/Tutorial:-Mor

ph-streams• Register queries• Pull Data• Push data through websockets• Simple SPARQLStream endpoint

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Querying live data streams

• Currently at:• http://streams.linkeddata.es/emt/sparqlstream

• Example• SELECT DISTINCT ?timeto ?obs

FROM NAMED STREAM <http://emt.linkeddata.es/data#busstops.srdf> [NOW - 59 S] WHERE { ?obs a <http://emt.linkeddata.es/data#BusObservation>. ?obs <http://purl.oclc.org/NET/ssnx/ssn#observedBy><http://transporte.linkeddata.es/emt/busstop/id/2018>. ?obs <http://purl.oclc.org/NET/ssnx/ssn#observationResult> ?output. ?output <http://emt.linkeddata.es/data#timeToBusValue> ?av. ?av <http://data.nasa.gov/qudt/owl/qudt#numericValue> ?timeto. }

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Some commands in Linux

• encoded_value=$(python -c "import urllib; print urllib.quote('''SELECT DISTINCT ?timeto ?obs FROM NAMED STREAM <http://emt.linkeddata.es/data#busstops.srdf> [NOW - 30 S] WHERE { ?obs a <http://emt.linkeddata.es/data#BusObservation>. ?obs <http://purl.oclc.org/NET/ssnx/ssn#observedBy><http://transporte.linkeddata.es/emt/busstop/id/2018>. ?obs <http://purl.oclc.org/NET/ssnx/ssn#observationResult> ?output. ?output <http://emt.linkeddata.es/data#timeToBusValue> ?av. ?av <http://data.nasa.gov/qudt/owl/qudt#numericValue> ?timeto. }''')")

• curl "http://streams.linkeddata.es/emt/sparqlstream?query=$encoded_value”

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Sample result

{ "head": { "vars": [ "timeto" , "obs" ] } , "results": { "bindings": [ { "timeto": { "datatype": "http://www.w3.org/2001/XMLSchema#string" , "type": "typed-literal" , "value": "0" } , "obs": { "type": "uri" , "value": "http://transporte.linkeddata.es/emt/busstop/id/2018/busline/9/observation/20/09/2013%2010:28:19%20%2B0200" } } ] }}

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Configuring Morph-streams

• Main ingredients:

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1. Data streams

2. Ontology (network)

3. R2RML mappings

Link both models

SSN Ontology with other ontologies

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W3C SSN Ontology

tool for modeling our sensor datacombine with domain ontologies

R2RML mappings

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busObservation a rr:TriplesMap; rr:logicalTable :emtStream;

rr:subjectMap [ rr:template "http://transporte.linkeddata.es/emt/busstop/id/{stopid}/busline/{lineid}/observation/{timed}"; rr:class emt:BusObservation; rr:graph emt:busstops.srdf ]; rr:predicateObjectMap [ rr:predicateMap [ rr:constant ssn:observedProperty ]; rr:objectMap [ rr:constant emt:time_to_bus ]]; rr:predicateObjectMap [ rr:predicateMap [ rr:constant ssn:observationResult ]; rr:objectMap [ rr:parentTriplesMap :busOutput; rr:joinCondition "" ]]; busOutput a rr:TriplesMap; rr:logicalTable :emtStream; …

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morph-streams: Ontology-based query rewriting

Query rewriting

Query ProcessingC

lien

t

SPARQLStream

[tuples][triples/

bindings]

Algebra expression

R2RML Mappings

SPARQLStream query processing

SELECT ?waittime ?stopFROM NAMED STREAM <http://emt.linkeddata.es/data#busstops.srdf> [NOW - 300 S]WHERE {?obs a emt:BusObservation;ssn:observedBy ?stop.ssn:observationResult ?result.?result emt:timeToBusValue ?av.?av qudt:numericValue ?waittime.}

SELECT timetobus, stopidFROM emt.win:time(300 second)

πTimetobus,stopid

ω300 -second

emt

Data translation

Esper

GSNCosmpull/

push Other

EMT Map4RDF iOS

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Map4RDFiOS

EMT Live Services

Waiting times feed

Get Bus stops data and location

SPARQLStream query

SPARQL query

Get Bus waiting times for a stop URI

Morph-streams

R2RML Mappings

SP

AR

QL

Str

eam

en

dp

oin

tS

PA

RQ

L

end

po

int

Map4RDF iOS

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Conclusions

• A bit of evangelization at EMT• Use of Web standards for Open Data• Use URIs for identifying stops, bus lines, etc• Use well defined sensor ontologies (SSN)• Use standard geolocation vocabularies• Mix static and streaming dat through URIs

• From the developer point of view• JSON results easy to consume• SPARQLstream endpoint through HTTP GET

• The Demo is a very simple but practical example of how this can be done fairly easily

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