An Open Source Linked Data Infrastructure for Publishing Geospatial Data

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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 - PowerPoint PPT Presentation

Text of An Open Source Linked Data Infrastructure for Publishing Geospatial Data

  • An Open Source Linked Data Infrastructure for Publishing Geospatial DataArif Shaon, Andrew Woolf, Shirley Crompton, Will Rogers, Mike Jackson, Robert Boszecarif.shaon@stfc.ac.uk

  • Place matterseverything happens somewhereLocation Strategy for the UKCombine information about placesStretch of roadSpeed limit ordersUnderground pipes, cables, ductsAccident statisticsBenefitsImprove decision makingDeliver better services

  • Querying location dataGIS Service (Known)GIS Service (Unknown)queryquery

  • INSPIREEU directive15th May 2007http://inspire.jrc.ec.europa.eu/ EU-wide infrastructure for spatial informationAll levels/scales of detailStandardModel ontology in UMLExpose as XMLAccess via web services

  • Semantic Web

  • Linked dataUse URIs as names for thingsUse HTTP URIs so that people can look up those namesWhen someone looks up a URI, provide useful information, using the standards (RDF, SPARQL)Include links to other URIs, so that they can discover more thingsTim Berners-Lee

  • Querying linked location dataLinked GIS Service (Known)Linked GIS Service (Unknown)Query (URI/SPARQL)Query (URI/SPARQL)

  • Querying linked location dataPotential for developing more flexible means of data sharing and accessibilityPotential for solving the problems of data harmonisation through complex web services

    Linked GIS Service (Known)Linked GIS Service (Unknown)Query (URI/SPARQL)Query (URI/SPARQL)

  • Location URIs for the UKDesigning URI sets for location, 2010STFC advised on developmentPart of the UK Location StrategyExtend INSPIRE to include linked data publication

  • URIs for the UK public sectorDesigning URI Sets for the UK Public Sector, 2009Identifier (id)http://education.data.gov.uk/id/school/121242 Document (doc)http://education.data.gov.uk/doc/school/121242 Representationhttp://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 workshttp://education.data.gov.uk/id/school/121242 (ID URI)ThingGeneric Documenthttp://education.data.gov.uk/doc/school/121242 (Doc URI)RDFHTMLhttp://education.data.gov.uk/doc/school/121242.rdfhttp://education.data.gov.uk/doc/school/121242.html303 redirectContentNegotiationapplication/rdf+xml winstext/html wins.../def/school (Def URI)definition

  • Location URIs for the UKSpatial Thing http://ea.gov.uk/id/HY/Watercourse/Thamesweb documenthttp://ea.gov.uk/doc/HY/Watercourse/Thamesrdfs:seeAlso http://ea.gov.uk/so/HY/Watercourse/ea-UKrivers/e7w1rdfs:seeAlso http://geotod/so/HY/Watercourse/stfc-strategi/4a97ov:similarTo http://ceh.nerc/so/HY/Watercourse/nerc-hydrodb/thames-001303 See other:Spatial Objecthttp://geotod/so/HY/Watercourse/stfc-strategi/4a97.rdfhttp://geotod/so/HY/Watercourse/stfc-strategi/4a97.htmlhttp://geotod/so/HY/Watercourse/stfc-strategi/4a97.kmlhttp://geotod/so/HY/Watercourse/stfc-strategi/4a97.gmlcontent negotiationId URI

  • GeoTOD-IIGeospatial Transformation with OGSA-DAIPublish spatial data as linked dataConform to UK Cabinet Office recommendationsLeverage existing related technologies

  • RequirementsVShttp://domain/104014/5sfd/2442 http://domain/myserver/mydata Opaque URIsBespoke human-readable URIs

  • How to interpret the guidelines?Spatial Object(SO URI)Spatial Object(SO URI)Spatial Thing(ID URI)Spatial Thing Metadata (Doc URI)???303 redirectWhat infoMaster Catalogue of Spatial Objects???Who owns it???RegisterSpatial Object(SO URI)

  • How to represent the ontology?INSPIREs UML conceptual modelsHow 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 ontologiesUK Environmental Agencys Bathing Water ontologyOGC GeoSPARQL working groupSubstantial tasks Require involvement of the wider community

  • Converting UML to RDFShttp://tiger.dl.ac.uk:8080/rdfsgenerator

  • Existing linked data solutionsExisting open source linked data server products

  • Existing linked data solutionsMay not always have database accessLimited scope for extending functionalityAdd GIS service for GML-based dataExpose GML formatsNeed an extensible solution

  • GeoTOD-II linked data framework

  • OGSA-DAI SO storeWeb resourcesRelational resourcesLinked SOStoreOGSA-DAI serviceGeotod-D2RQRDBWorkflowGenerate RDB-specific SQL using mapping file

    SPARQL query+output formattingD2RQ Mapping FileSQL

    GeoServer WSGML query

  • GeoTOD prototypeTest dataOrdnance Survey Strategi data setUK natural and man-made featuresESRI shapefiles => SQLOntology generationRelevant INSPIRE models e.g. HY, TNINSPIRE UML => XML Schema => RDFSEasier than UML => RDFS direct

  • GeoTOD-II demo server

    http://tiger.dl.ac.uk:8080/geotodls/index.html

  • Spatial thing HTMLhttp://tiger.dl.ac.uk:8080/id/TN/RailwayStationNode/heathrow-terminal-4-station

  • Spatial thing RDFhttp://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

  • ConclusionsGeoTOD frameworkConforms to UK Cabinet Office location URIsPlug-in support for new data sources or representationsShould benefit projects and organisations looking to deploy existing geospatial data assets as linked dataAdvanced Climate Research Infrastructure for Datahttp://www.cru.uea.ac.uk/cru/projects/acrid/index.htmFurther workEngage with linked data and geospatial communitiesDevelop into efficient and reliable producthttp://sourceforge.net/projects/geotod

    GeoTOD ran from July to December and was funded by EPSRC via OMII-UK (latterly the SSI).Thank the organisers.

    **GeoTOD-II looked at location or geospatial data.Users or tools can submit query to GIS e.g. via web service interfaces.But how to build generic tool to query these GIS servers and others.Or help users exploit their existing knowledge.

    *Legally binding.Easy discovery of, access to, sharing of and combination of spatial information from all across the EU.

    *Underlying principles of linked data have influenced many open data initiatives.

    *LD provides a means of querying location data in a consistent way via a uniform API suitable for use by humans (via a browser) and tools.

    **In recognition of the importance of geospatial data.Cabinet Office (2010)Extends the generic Designing URI Sets for the Public Sector guidelines mentioned previously.UK location URIs based on INSPIRE. Promote LD in INSPIRE.

    *One is the UK Open Linked Data Initiative, data.gov.uk, promoting linked data as a means of exposing government and public authority data.Identifier e.g. Some Grammar School. A thing a department or agency is responsible for. Concept and reference e.g. id, school (concept) and reference e.g. 121241.Document describes Some Grammar School. Explicitly linked by the Identifier publisher. May be many documents describing the Identifier. Document may have different representations e.g. HTML, RDF (See Cool URIs for the semantic web, W3C)Definition e.g. A school is. ontology URI.There are also set URIs.

    *Content negotiation done via HTTP.

    *Spatial Thing things that have spatial extent or position e.g. a place, building, river.Note the id as before from the public sector URIs.HY is an INSPIRE theme code (Hydrography).Watercourse is a spatial object type or class.This redirects to the doc as before.Now the doc links to so spatial objects, directly corresponds to the INSPIRE concept of SO.Spatial Object abstraction of aspects of a Spatial Thing e.g. shape, name, boundary, adjacenciesstfc-strategi is a namespace.4a97 is a local name.Similar specification for def URIs, mapping to INSPIRE conceptual model definitions.

    *A more ambitious original project was bid for, hence the II.OGSA-DAI distributed data solution, distributed by OMII-UK, established UK e-science framework.

    *Need a community ontology so can understand data model and effectively exploit the data. Should allow continued use of existing systems also removes barrier to adoption gradual change, not replace. Need to balance opaque URIs versus human-readable URIs.

    *Pragmatic interpretation of the Designing URI sets for location guidelinesWhat information is provided at a doc URI? We adopted a list of all the associated do URIs (a master catalog).This though implies ownership of the id/doc URIs and a registration process.

    *INSPIRE used RDF ontologies.OGC SPARQL extensions for spatial queries includes certain OWL definitions for geospatial features.

    *UKEA server implements the guidelines.National Geography Institute of Spain.Open source linked data services. Typically support relational databases and mapping files which specify mapping between relational and RDF schema.

    *Adding a non-relational resource would require substantial re-implementation of the underlying architecture possible but may be impractical.May not always have access to a database directly.LD recommends supporting a number of formats.GML is a prevalent format for exchanging geospatial data.How to support this added value?

    *CN determines request format which determines CV.CV is an extensibility point can plug-in other representations e.g. GML.LS used by CVs to generate responses to requests, for DOC, DEF, SO.Spring MVC Java framework.Handle HTTP requests and responses.Map views to linked storesLinked stores (resources) id, doc, so, def extensibility point. Here, two types RDF triple store for id, doc, def and OGSA-DAI for so.Also supports Geoserver WFS application for access to GML

    *Used OGSA-Dai to provide uniform access to different types of geospatial data resou