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Linked (Geo) Data - Adding a Spatial Dimension to the Web of Data

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Claus Stadler, Sören Auer AKSW Research Group University of Leipzig - Talk at "Vienna Semantic Web Meetup" in Graz on Sept 6, 2011

Claus Stadler, Sören Auer AKSW Research Group University of Leipzig - Talk at "Vienna Semantic Web Meetup" in Graz on Sept 6, 2011

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  • 1. Linked (Geo) Data Adding a Spatial Dimension to the Web of Data http://linkedgeodata.org Claus Stadler, Sören Auer AKSW Research Group University of LeipzigUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 1
  • 2. Structure ● Linked Data ● LinkedGeoData ● Architecture ● Mapping to RDF/OWL ● Interlinking ● Applications ● Issues & Future work ● Open Governmental Geo DataUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 2
  • 3. The emerging Web of Linked DataUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 3
  • 4. Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 4
  • 5. LinkedGeoData Conversion, interlinking and publishing of OpenStreetMap.org data sets as RDF.Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 5
  • 6. Motivation ● Ease information integration tasks that require spatial knowledge, such as ● Offerings of bakeries next door ● Cinemas nearby and their programs ● Historical sights along a bicycle track ● Therefore use RDF/OWL in order overcome structural and semantic heterogeneity. ● LOD cloud contains data sets with spatial features ● e.g. GeoNames, DBpedia, US census, EuroStat ● But: they are restricted to popular or large entities like countries, famous places etc. ● OSM offers buildings, roads, mailboxes, trash bins/recyling, ...Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 6
  • 7. What do we offer? ● Very large RDF knowledge base derived from OpenStreetMap ● REST API, static & live SPARQL endpoints ● Update propagation of the added and removed triples ● 845.000 Interlinks with DBpedia, GeoNames, and FAO ● LGD-BrowserUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 7
  • 8. ArchitectureUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 8
  • 9. OpenStreetMap - Datamodel ● Basic entities are: ● Nodes Latitude, Longitude ● Ways Sequence of nodes ● Relations Associations between any number of nodes, ways and relations. ● Each entity may be described with tags: key-value pairs, such as (amenity, school)Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 9
  • 10. Example: Leipzigs ZooUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 10
  • 11. OSM entities → RDF ● Three types of mappings based on (osm-id, key, value) ● Text – (5, name, Leipzig) → lgd:node5 rdfs:label ”Leipzig” – (5, name:de, Leipzig) → lgd:node5 rdfs:label ”Leipzig”@de ● Datatype properties – (6, seats, 4) → lgd:node6 lgdo:seats ”4”^^xsd:integer ● Classes/object properties – (7, amenity, school) → lgd:node7 a lgdo:School – (8, amenity, rare value) → lgd:node8 a Amenity – (9, religion, hindi) → lgd:node9 lgdo:religion lgdo:HindiUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 11
  • 12. Ontology ● Text, class, and object property mappings manually crafted ● Subclass relations inferred from class-mappings: (..., amenity, school) → ... a School (..., amenity, rare value) → ... a Amenity School subClassOf Amenity ● Automatically mapped OSM keys with mostly numerical values to datatype properties ● boolean, integer, floatUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 12
  • 13. Ontology● Enriched classes and properties with multilingual labels from TranslateWiki ● http://translatewiki.net● Imported icons for 90 classes from the freely available icon collection from the SJJB Management ● http://www.sjjb.co.uk/mapicons/Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 13
  • 14. OntologyUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 14
  • 15. Instance DataUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 15
  • 16. Statistics (2011-Feb-23) ● 222.539.712 Triples ● 6.666.865 Ways ● 5.882.306 Nodes ● Among them ● 352.673 PlaceOfWorship ● 60.573 RailwayStation ● 59.468 Recycling ● 50.955 Town ● 30.099 Toilet ● 7.222 CityUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 16
  • 17. DBpedia MappingGiven a point from DBpedia, GeoNames, …, query LGD points with certain types within a maximum distanceBasic idea (performed with Silk): ● Find most similar type(s) in LGD for a type in another knowledge base ● Compute spatial score ● Compute name similarity (rdfs:label) ● Combine both scores ● Depending on final score, either automatically accept/reject links or mark for manual verification. Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 17
  • 18. How to access the data? ● Rest Interface (based on Postgis DB, full osm dataset loaded, > 1billion triples) ● Supports limited queries (e.g. circular/rectangular area, filtering by labels) ● Sparql Endpoints (based on Virtuoso DB, subset of osm dataset loaded, ~222mio triples) ● Static (http://linkedgeodata.org/sparql) ● Live (http://live.linkedgeodata.org/sparql) ● Downloads (same data as in the SPARQL endpoints, http://downloads.linkedgeodata.org)Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 18
  • 19. Applications: LinkedGeoData Browser http://browser.linkedgeodata.orgUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 19
  • 20. Applications: Generic spatial data browsing widgetsUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 20
  • 21. Applications: MovieGoer ● MovieGoer – Scrapes websites with information about the programs of cinemas in Innsbruck and Munich – Interlinked with LinkedGeoData in order to obtain address information – During development: missing cinemas added to OSM; became available for interlinking through LGD-Live. http://lokino.sti2.at/Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 21
  • 22. More Applications ● Layar Augmented reality browser for mobile phones, features a LGD layer http://layar.com ● Vicibit Generates embeddable HTML code for displaying a map of POIs of certain types in a specified area http://vicibit.linkedgeodata.orgUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 22
  • 23. Issues & Future work ● Converting all OSM data to RDF not feasible: > 1.000.000.000 nodes → only a subset of OSMs data available via the SPARQL endpoints ● Virtuoso only supports point geometries ● Possible solution: Rewriting SPARQL queries to the OSM SQL schema ● Work in progress, no estimate on a release yetUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 23
  • 24. Issues and Future Work ● Investigating further applications of LGD, such as using the LGD knowlegde base for named entity recognition/resolutionUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 24
  • 25. Open Governmental Geo Data ● Most governmental data has a spatial dimension ● transportation, statistics, finances, etc. ● Geo Data is a driver in the Open Government Data realm ● ordenance survey, geodata.gov.gr, … ● It is still difficult to extract, publish, interlink, author and visualize Governmental Linked Geo Data ● LOD2 Stack (ckan integration, browsing widgets, integrated comprehensive tool compilation)Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 25
  • 26. Best practices ● Reuse of vocabularies ● vCard: address information, phone & fax ● Good Relations: Opening hours, product descriptions ● GeoOWL: latitude, longitude, polygons – GeoSPARQL Ontology ● Foaf: based_near ● Dublin core (dc): Document meta data ● … http://www.leipzig.de/de/buerger/jugend/betreuung/kitas/Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 26
  • 27. TransportationUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 27
  • 28. Comprehensive Knowledge Archive Network (CKAN)Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 28
  • 29. Financial TransparencyUniversität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 29
  • 30. The End Thanks for your Attention!Universität Leipzig ▪ Agile Knowledge Engineering and Semantic Web (AKSW) Authors: Sören Auer, Jens Lehmann, Claus Stadler Slide 30

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