Meaningful URIs for Linked Sensor Data
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Towards Meaningful URIs for Linked Sensor Data K. Janowicz, A. Broering, C. Stasch, T. Everding Towards Digital Earth Workshop @ FIS2010, Berlin September 20th, 2010
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Sensor data is stored and published using OGC’s Observation & Measurement specifications as underlying data model. With the advent of volunteered geographic information and the Semantic Sensor Web, work on an ontological, i.e. conceptual, model gains importance within the Sensor Web Enablement community. In contrast to a data model, an ontological approach abstracts from implementation details by focusing on modeling the real world from the perspective of a particular domain or application and, hence, restricts the interpretation of the used terminology towards their intended meaning. The shift to linked sensor data, however, requires yet another perspective. Two challenges have to be addressed, (i) how to refer to changing and frequently updated data sets such as stored in Sensor Observation Services using Uniform Resource Identifiers, and (ii) how to establish meaningful links between those data sets, i.e., observations, sensors, features of interest, observed properties, and further participants in the measurement process. In this short paper we focus on the problem of assigning meaningful URIs. Get the paper here: http://ifgi.uni-muenster.de/~arneb/de2010_final_submission.pdf
Transcript of Meaningful URIs for Linked Sensor Data
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
...
Arne Broering - [email protected]
Sensor Web Enablement (SWE)
http://www.ogcnetwork.net/swe
Web Service interfaces & data encodings
Building blocks for a Sensor Web
Arne Broering - [email protected]
OGC®
SWE Functionality
Project: GITEWS
Sensor Observation Service
SensorML
O&M
GetCapabilities
DescribeSensor
GetObservation
GML GetFeatureOfInterest
Arne Broering - [email protected]
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“
Arne Broering - [email protected]
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
Arne Broering - [email protected]
Goal: Linked Sensor Data
To improve browsing & discovery of sensor data
Arne Broering - [email protected]
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
...
Arne Broering - [email protected]
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…
Arne Broering - [email protected]
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?
Arne Broering - [email protected]
Linked Sensor Data
Requirements
Linked Data Model (in RDF)
Links between data chunks
Unified Resource Identifier (URI) Scheme
Arne Broering - [email protected]
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
Arne Broering - [email protected]
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
Arne Broering - [email protected]
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/-/..
Arne Broering - [email protected]
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
Arne Broering - [email protected]
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
Arne Broering - [email protected]
Demo: RESTful SOS Proxy
http://v-swe.uni-muenster.de:8080/52n-OXF-WS/RESTful/sos
Questions?
Thank you!
Arne Broering
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
