1. The Web of Data and its Five Stars
Richard Cyganiak, DERI, NUI Galway
@cygri
6 June 2012
Realising and Exploiting the EU data cloud
European Data Forum, Copenhagen, Denmark

2. Generating insight from data
• Today, data is abundant
• New middlemen find new ways of getting data to the end user
• Supply and demand for data higher than ever
• Analyst's problem is no longer a lack of relevant data, but:
• Understanding data
• Assessing applicability
• Getting it into the right form for use
• Similar problems inside and outside of the firewall

3. From the Web
to the Web of Data

4. Tim Berners-Lee’s 5-star plan for an open web of data
★
Make data available on the Web under an open license
★★
Make it available as structured data
★★★
Use a non-proprietary format
★★★★
Use URIs to identify things
★★★★★
Link your data to other people’s data
to provide context

5. The 0th star
• Data catalog with good metadata
• Make your data findable

7. Data on the Web, Open License
★

8. Open Data

9. Government data catalogs

10. Open vs. Closed
Data used to be closed by default.
In the future, it will be open by default.

11. Is open data just for governments?

15. Good reasons against opening data
• Privacy
• Competitive advantage
• Producing data and charging for it as business model
• Can't get license from upstream

16. Business models
Scott Brinker, http://www.chiefmartec.com/2010/01/7-business-models-for-linked-data.html

17. Data licenses
http://opendefinition.org/licenses/

18. Structured Data
★★

19. Enabling re-use
• Delivering data to end users in different forms
• Combining data with other data
• 3rd party analysis of data

20. Formats in government data
• Good for re-use: MS Excel, CSV, XML, JSON, Microdata
• Not so good for re-use: Pure websites, MS Word
• Bad for re-use: PDF
• Really bad for re-use: Only charts/maps without numbers

21. Symptom: Screenscraping

22. Non-Proprietary Formats
★★★

23. Specialist formats
• Specialist tools often have specialist formats
• Few people have the tools
• Expensive
• Difficult to re-use
• (Geospatial tools, statistics packages, etc.)

25. Non-proprietary formats, open standards
• CSV (dead simple)
• XML
• JSON
• RDF (good for 4+5 stars)
• OGC web services
• OAI-ORE web services

26. Use URIs as Identifiers
★★★★

27. http://www.bbc.co.uk/music/artists/79239441-bfd5-4981-a70c-55c3f15c1287

28. http://data.ordnancesurvey.co.uk/id/postcodeunit/HA99HD

29. http://opencorporates.com/companies/us_vt/F013910

31. Turning local identifiers into URIs–Why?
• Make them globally unique
• Clarify authority
• Make them resolvable
• Make them linkable
http://data.ordnancesurvey.co.uk/id/7000000000017765

32. The schema level
By using URIs, connections that existed only in people's
minds can be put explicitly into the data model.

33. Include Links to Other Data
★★★★★

34. Hyperlinks are the soul of the Web.
The Web of Data is no different.

35. Data links
Central Contractor Registration (CCR)
Geonames

36. Linked Data Principles
1. Use URIs to name things (not only documents, but also people, locations,
concepts, etc.)
2. To enable agents (human users and machine agents alike) to look up those
names, use HTTP URIs
3. When someone looks up a URI, provide useful information (structured data in
RDF, SPARQL).
4. Include links to other URIs allowing agents to discover more things
http://www.w3.org/DesignIssues/LinkedData.html

38. Summary
• In the future, data will be open by default, unless good reason not to
• Emergence of a web of data
• “Five-star plan” for getting there, dataset by dataset
• 2 stars: re-usable data!
• 3 stars: open standards!
• 4+5 stars: connect the silos!

39. Thank You!
richard@cyganiak.de
@cygri