1. RAGLD Training Session Ordnance Survey 26th September 2013

2. Your Hosts • Ian Millard, Senior Technologist • Hugh Glaser, Chief Architect

3. Agenda • Linked Data Introduction • RAGLD Introduction • REST Through Rithmetic • Relationship Stores through Relatives • Republishing RDF • Break • Simple geo-services – sameAs, differentFrom, contains, touches services • Searching • Complex geo-services – indexing & analysis • Demonstration – delivering an answer for Bed & Breakfast en route • Visualisation tools

4. 1. Linked Data Introduction • Spatial data infrastructures • Linkable data – use of unique identifiers John Goodwin’s slide

5. Towards a web of linked data… John Goodwin’s slide

6. Linked Data Principles The four micro principles of the Semantic Web 1. All entities of interest, such as information resources, real-world objects, and vocabulary terms should be identified by URI references. 2. URI references should be dereferenceable, meaning that an application can look up a URI over the HTTP protocol and retrieve RDF data about the identified resource. 3. Data should be provided using the RDF/XML syntax 4. Data should be interlinked with other data.

7. 1. Use URIs as names for things • Everything • If you don’t name something you can’t talk about it • Things of course • Year of publication • Ideas • … • Cool URIs • Think of the consumer/customer • https://secure.ecs.soton.ac.uk/gizmos/person_by_username.php?username=hg • https://secure.ecs.soton.ac.uk/person/username/hg • RESTful Interfaces • Ambiguity • URIs help to avoid it, especially if you…

8. 2. Use HTTP URIs so that people can look up those names • HTTP URI names come with an excellent look up mechanism • And ownership, etc.

9. 3. When someone looks up a URI, provide useful information, using the standards (RDF, SPARQL) • So they know what you mean • Deliver some human readable data • html • Deliver some machine processable data • RDF • JSON • CSV • text

10. Essential RDF • Statements about resources in the form of subject-predicate-object • A knowledge representation language for the Web • Represents information as sets of triples – subject verb object • Every element of a triple can be a URI or a concrete value (literal) • Sets of RDF triples can be represented as graphs • Ontologies define vocabularies, types and relationships • Agreed URIs facilitate linkage between datasets

11. 442356 114001 Easting Northing ../SO171DP ../70..17707 District Ward ../70..37256 Within Name Name Bevois Southampton John Goodwin’s slide

12. URIs The City of Southampton: http://data.ordnancesurvey.co.uk/id/7000000000037256 Bevois: http://data.ordnancesurvey.co.uk/id/7000000000017707 The postcode unit SO17 1DP: http://data.ordnancesurvey.co.uk/id/postcodeunit/SO171DP

13. Triples <http://data.ordnancesurvey.co.uk/id/postcodeunit/SO171DP> <http://data.ordnancesurvey.co.uk/ontology/postcode/ward> <http://data.ordnancesurvey.co.uk/id/7000000000017707> . <http://data.ordnancesurvey.co.uk/id/postcodeunit/SO171DP> <http://data.ordnancesurvey.co.uk/ontology/postcode/district> <http://data.ordnancesurvey.co.uk/id/7000000000037256> . <http://data.ordnancesurvey.co.uk/id/7000000000017707> <http://www.w3.org/2000/01/rdf-schema#label> "Bevois" . <http://data.ordnancesurvey.co.uk/id/7000000000037256> <http://www.w3.org/2000/01/rdf-schema#label> "Southampton" . <http://data.ordnancesurvey.co.uk/id/7000000000017707> <http://data.ordnancesurvey.co.uk/ontology/spatialrelations/within> <http://data.ordnancesurvey.co.uk/id/7000000000037256> . <http://data.ordnancesurvey.co.uk/id/7000000000017707> <http://www.w3.org/2002/07/owl#sameAs> <http://statistics.data.gov.uk/id/statistical-geography/E05002457> .

14. 4. Include links to other URIs. so that they can discover more things • “Foreign” URIs • dbpedia:Southampton_University • Equivalence • owl:sameAs • skos:exactMatch • … http://rdf.ecs.soton.ac.uk/person/2686 SameAs http://southampton.rkbexplorer.com/id/person-02686 SameAs http://dbpedia.org/resource/Nigel_Shadbolt

15. 2. RAGLD Introduction

16. About RAGLD • A collaborative project between Ordnance Survey, the University of Southampton and Seme4 Ltd • Part-funded by the Technology Strategy Board‘s “Harnessing Large and Diverse Sources of Data” programme • 18 month long project. Started Oct 2011. Completed March 2013 • Building tools to enable developers to make greater use of linked data • So Diverse it is hard to describe • There is much that we could focus on

17. Linked Data IDs, RDF and RESTful Services • REST - http://en.wikipedia.org/wiki/Representational_state_transfer • Essentially, for this demonstration: • Use HTTP methods GET, PUT, (POST) & DELETE • GET • Retrieve a representation of the addressed member of the collection, expressed in an appropriate Internet media type • No side-effects • PUT • Replace the addressed member of the collection, or if it doesn't exist, create it • idempotent • DELETE • Delete the addressed member of the collection • idempotent • MIME (Internet Media) Types are important to both • text/html • text/plain • application/json • application/rdf+xml • text/turtle

18. Tools and Services • Data Enhancement Services • Data Transformation Services • Relationship Management Services • Ingestion Services • Publishing Services • Spatial Query Services • Visualisation Components • Workflow Management • Federation of Services • Proxy Services

19. A Challenge - SeeUK

20. 150M URIs 43M Distinct The Web of Data has many equivalent URIs. This sameAs service helps you manage co-refs between different data sets.

21. 3. REST Through `Rithmetic • Let’s Go! • http://demo{NN}.data.seme4.com • NN = {30..40} • http://demo30.data.seme4.com/services/arithmetic/

22. 4. Relationship Stores through Relatives • Relationship services maintain pairs { symbolA, symbolB } • These can be URIs, numbers, or text strings • Most basic store gives back what you put in • Can specify additional properties • symmetric, transitive, reflexive, inverse

23. 5. Publishing RDF • Linked data publishing often seen as difficult • RDF, triplestores, SPARQL, complex redirects, etc • RAGLD has basic support built in (RESTful, of course!) • http://demoXX.data.seme4.com/id/joe • Stick your RDF in a file, and then PUT on the server • Lets try and have a go…

24. Break

25. 6. More of a geospatial focus • Geospatial data is full of relationships between entities • We can use RAGLD relationship services to make factual data about geospatial features readily accessible • sameAs / different From • touches (symmetric) • contains / within (transitive, will compute automatically) • “connected” (use touches but apply symmetric + transitive) • “one hop away” (constrain number of hops)

26. 7. Searching • Relationship stores can also be used as lookup/search services • useful to reconcile multiple identifiers to a single URI • Store pairs of { URI, label } • Exact match, partial match, regular expressions • Can federate search over a number of relationship stores • Eg http://geospatial.data.seme4.com/postcode/

27. 8. Dealing with geospatial features • RAGLD services can use a common function to acquire (“ingest”) geospatial features from a number of sources • POST a raw geospatial feature (GeoJSON, GML, WKT, SHP.zip) • Access geospatial data available at a URI (either static, or a service) • Acquire geospatial data from RDF • must either have coordinate point, or checks a number of predicates for boundary data • again, this can be a static document, eg Linked Data resource, or the output of a service • http://geospatial.data.seme4.com/services/geo/ingest/

28. 9. “Proper” geospatial services • Two main geospatial services, backed by PostGIS • primarily developed by Tony Joyce

29. 10. Demonstration –Bed & Breakfasts en route • Find convenient bed and breakfasts on a road-trip(within 10km of my route) • Fictitious dataset of Bed & Breakfasts • eg http://demo.data.seme4.com/id/bnb-1234 • (unfortunately many are at sea!) • Geospatial index of these locations • http://geospatial.data.seme4.com/services/geo/bnb/

30. 10. Demonstration –Bed & Breakfasts en route ingest ( fetch ( within ( buffer( route ) ) ) )

31. 11. App building tools • Many services can be easily accessed directly via AJAX calls • RESTful invocation via simple “cool” URIs • Request JSON or GeoJSON output • Eg search – http://demoXX.data.seme4.com/example-search.html

32. 11. App building tools • Visualisation / mapping library • Javascript “glue” to easily link outputs from service(s) and display on a map • Based around Leaflet and a couple of plugins • Used by Guy Heathcote to develop RAGLD demonstrator • http://demoXX.data.seme4.com/visualisation.zip