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An Open Source Linked Data Infrastructure for Publishing Geospatial Data. Arif Shaon, Andrew Woolf, Shirley Crompton, Will Rogers, Mike Jackson , Robert Boszec arif.shaon@stfc.ac.uk. “Place matters…”. “everything happens somewhere” Location Strategy for the UK
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An Open Source Linked Data Infrastructure for Publishing Geospatial Data Arif Shaon, Andrew Woolf, Shirley Crompton, Will Rogers, Mike Jackson, Robert Boszec arif.shaon@stfc.ac.uk
“Place matters…” • “everything happens somewhere” • Location Strategy for the UK • Combine information about places • Stretch of road • Speed limit orders • Underground pipes, cables, ducts • Accident statistics • Benefits • Improve decision making • Deliver better services
Querying location data query GIS Service (Known) query GIS Service (Unknown)
INSPIRE • EU directive • 15th May 2007 • http://inspire.jrc.ec.europa.eu/ • EU-wide infrastructure for spatial information • All levels/scales of detail • Standard • Model ontology in UML • Expose as XML • Access via web services
Linked data • Use URIs as names for things • Use HTTP URIs so that people can look up those names • When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL) • Include links to other URIs, so that they can discover more things Tim Berners-Lee
Querying linked location data Query (URI/SPARQL) Linked GIS Service (Known) Query (URI/SPARQL) Linked GIS Service (Unknown)
Querying linked location data Query (URI/SPARQL) • Potential for developing more flexible means of data sharing and accessibility • Potential for solving the problems of data harmonisation through complex web services Linked GIS Service (Known) Query (URI/SPARQL) Linked GIS Service (Unknown)
Location URIs for the UK • “Designing URI sets for location”, 2010 • STFC advised on development • Part of the UK Location Strategy • Extend INSPIRE to include linked data publication
URIs for the UK public sector • “Designing URI Sets for the UK Public Sector”, 2009 • Identifier (id) • http://education.data.gov.uk/id/school/121242 • Document (doc) • http://education.data.gov.uk/doc/school/121242 • Representation • http://education.data.gov.uk/doc/school/121242.html • http://education.data.gov.uk/doc/school/121242.rdf • Definition / ontology (def) • http://education.data.gov.uk/def/school/
How it works http://education.data.gov.uk/id/school/121242 (ID URI) definition Thing .../def/school (Def URI) 303 redirect http://education.data.gov.uk/doc/school/121242 (Doc URI) Generic Document application/rdf+xml wins text/html wins Content Negotiation RDF HTML http://education.data.gov.uk/doc/school/121242.rdf http://education.data.gov.uk/doc/school/121242.html
Location URIs for the UK ‘Id’ URI ‘Spatial Thing’ http://ea.gov.uk/id/HY/Watercourse/Thames ‘303 See other:’ ‘Doc’ URI ‘web document’ http://ea.gov.uk/doc/HY/Watercourse/Thames rdfs:seeAlso http://ea.gov.uk/so/HY/Watercourse/ea-UKrivers/e7w1 rdfs:seeAlso http://geotod/so/HY/Watercourse/stfc-strategi/4a97 ov:similarTo http://ceh.nerc/so/HY/Watercourse/nerc-hydrodb/thames-001 ‘content negotiation’ ‘Spatial Object’ http://geotod/so/HY/Watercourse/stfc-strategi/4a97.rdf http://geotod/so/HY/Watercourse/stfc-strategi/4a97.html http://geotod/so/HY/Watercourse/stfc-strategi/4a97.kml http://geotod/so/HY/Watercourse/stfc-strategi/4a97.gml ‘So’ URI
GeoTOD-II • Geospatial Transformation with OGSA-DAI • Publish spatial data as linked data • Conform to UK Cabinet Office recommendations • Leverage existing related technologies
Requirements Linked Data Service Community Data Model/ Vocabulary/Ontology Existing data and GIS services Bespoke human-readable URIs Opaque URIs VS http://domain/104014/5sfd/2442 http://domain/myserver/mydata
How to interpret the guidelines? Spatial Thing (ID URI) Spatial Thing Metadata (Doc URI) 303 redirect ??? What info Master Catalogue of Spatial Objects Spatial Object (SO URI) ??? Spatial Object (SO URI) Spatial Object (SO URI) Who owns it ??? Register
How to represent the ontology? • INSPIRE’s UML conceptual models • How to transform to OWL/RDF? • How to address import of ISO schemas? e.g. • ISO 19107 (spatial schemas) • ISO 19115 (geospatial meta data) • Unofficial and incomplete ontologies • UK Environmental Agency’s Bathing Water ontology • OGC GeoSPARQL working group • Substantial tasks • Require involvement of the wider community
Converting UML to RDFS http://tiger.dl.ac.uk:8080/rdfsgenerator
Existing linked data solutions Existing Linked-Data Services UK Environmental Agency linked data server (data.ordnancesurvey.co.uk) Spanish geo-linked data server (geo.linkeddata.es) Existing open source linked data server products
Existing linked data solutions • May not always have database access • Limited scope for extending functionality • Add GIS service for GML-based data • Expose GML formats • Need an extensible solution
OGSA-DAI SO store Web resources Linked SO Store GeoServer WS OGSA-DAI service GML query Workflow SPARQL query + output formatting SQL Relational resources RDB Geotod-D2RQ Generate RDB-specific SQL using mapping file D2RQ Mapping File
GeoTOD prototype • Test data • Ordnance Survey Strategi data set • UK natural and man-made features • ESRI shapefiles => SQL • Ontology generation • Relevant INSPIRE models e.g. HY, TN • INSPIRE UML => XML Schema => RDFS • Easier than UML => RDFS direct
GeoTOD-II demo server http://tiger.dl.ac.uk:8080/geotodls/index.html
Spatial thing HTML http://tiger.dl.ac.uk:8080/id/TN/RailwayStationNode/heathrow-terminal-4-station
Spatial thing RDF http://tiger.dl.ac.uk:8080/id/TN/RailwayStationNode/heathrow-terminal-4-station
Spatial object GML http://tiger.dl.ac.uk:8080/so/TN/RailwayStationNode/tn-ra/984
Conclusions • GeoTOD framework • Conforms to UK Cabinet Office location URIs • Plug-in support for new data sources or representations • Should benefit projects and organisations looking to deploy existing geospatial data assets as linked data • Advanced Climate Research Infrastructure for Data • http://www.cru.uea.ac.uk/cru/projects/acrid/index.htm • Further work • Engage with linked data and geospatial communities • Develop into efficient and reliable product • http://sourceforge.net/projects/geotod