Towards Meaningful URIs

for Linked Sensor Data

K. Janowicz, A. Broering, C. Stasch, T. Everding

Towards Digital Earth Workshop @ FIS2010, Berlin

September 20th, 2010

Vision

World Wide Web is for websites

HTTP

HTML

...

Sensor Web is for sensors

O&M

SOS

SPS

...

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Sensor Web Enablement (SWE)

http://www.ogcnetwork.net/swe

Web Service interfaces & data encodings

Building blocks for a Sensor Web

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OGC®

SWE Functionality

Project: GITEWS

Sensor Observation Service

SensorML

O&M

GetCapabilities

DescribeSensor

GetObservation

GML GetFeatureOfInterest

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Observations & Measurements

Feature of Interest:= „SeminarisHotelBerlin“

Sensor := „Weatherstation_Dahlem“

23 m/s 16.9.2010 13:45

Result

Unit of Measure

Sampling TimeObserved Property:= „Windspeed“

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Observation

Observations & Measurements

class O&M

Observ ation

- samplingTime: Time

Procedure PropertyType «FeatureType»

AnyFeature

Any

+procedure

1

+observedProperty

1

+propertyValueProvider

0..*

+featureOfInterest

1

+result

1

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Goal: Linked Sensor Data

To improve browsing & discovery of sensor data

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Vision

World Wide Web is for websites / documents

HTTP

HTML

...

Sensor Web is for sensors

SOS

O&M

...

Linked Data Web is for linked data

RDF

...

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Linked Data

Shift from linked documents to linked data

Establish links:

Documents: HTML

Data: RDF

Already available linked data:

people, companies, publications, books, movies, music, television

programs, genes, proteins…

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Linked Data

Example usage:

What proteins are involved in signal transduction AND are

related to pyramidal neurons?

Google search: 200.000 hits, NO results

Linked Data search: 32 hits, 32 results

(see TED Talk from Berners-Lee)

Example “GEO”-usage:

Which sensors are located along the river Rhine AND

measure water level higher than 4,50 m during yesterday?

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Linked Sensor Data

Requirements

Linked Data Model (in RDF)

Links between data chunks

Unified Resource Identifier (URI) Scheme

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RESTful SOS Proxy for Linked Sensor Data

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URI Scheme for Linked Sensor Data

Access to features of interest:

http://my.authority.org/foi

Example:

http://my.authority.org/foi/SeminarisHotelBerlin

Access to sensors:

http://my.authority.org/sensors

Example:

http://my.authority.org/sensors/Weatherstation_Dahlem

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URI Scheme for Linked Sensor Data

Access to observations:

http://my.authority.org/observations

Thematic filter:

../observation/<sensor>/<foi>/<observed property>

Example:

../observations/Weatherstation_Dahlem/SeminarisBerlin/windSpeed

Example “Wildcard”:

../observations/-/-/windSpeed

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URI Scheme for Linked Sensor Data

Temporal filter (aligned with ISO8601):

../observation/sensor/foi/observed property/<start date>/<end date>

<start date>:= <year>/<month>/<day>/<hour>/<minute>/<second>

<end date> := <year>/<month>/<day>/<hour>/<minute>/<second>

Example:

February 2010 - 1st July 2010 at 13:05:

../2010/02/-/-/-/-/2010/07/01/13/05/-/..

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URI Scheme for Linked Sensor Data

Spatial filter:

../<start>/<end>/<minLat>_<minLong>_<maxLat>_<maxLong>_<crs>

Example:

../52.12_7.45_52.34_7.56_urn:ogc:def:crs:EPSG::4326

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RESTful SOS Architecture

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Outlook

Linked Data model (O&M RDF)

Accepted by W3C Semantic Sensor Network Incubator Group

(http://www.w3.org/2005/Incubator/ssn/)

Meaningful Links within model

Include other SWE standards:

SensorML RDF

RESTful SES Proxy

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Demo: RESTful SOS Proxy

http://v-swe.uni-muenster.de:8080/52n-OXF-WS/RESTful/sos

Questions?

Thank you!

Arne Broering

broering@52north.org

52°North RESTful SOS Proxy: http://52north.org/RESTFul_SOS

52°North Semantics Community: http://52north.org/semantics

IfGI SWSL: http://swsl.uni-muenster.de

IfGI MUSIL: http://musil.uni-muenster.de