The Joy of DataA cookbook for publishing Linked Data on the Web

10 minute brief to the W3C Gov’t Linked Data Working Group29-June 2011

Bernadette Hylandbhyland@3roundstones.com

1Thursday, June 23, 2011

Agenda• Setting the scene

• Ingredients ... we use a cooking analogy

• Open standards & best practices

• Data modeling without context

• Social contract as a publisher

• Next steps

2Thursday, June 23, 2011

Setting the scene ...

where should we focus?

3Thursday, June 23, 2011

We’ll review •Converting data into RDF

•The social contract publishers make

•The importance of announcing

•Where to turn for guidance

4Thursday, June 23, 2011

• A different way of thinking about data

• The Open World Assumption

• Lots of URIs

• To be citizen of the world (not everyone speaks English)

• To publish useful information & announce it!

5Thursday, June 23, 2011

Publish machine & human readable content

• Machine readable format

• Human-readable descriptions of your data set

• Increase visibility with search engines

• Include RDFa or other microformats

• Publish a voID description of your RDF dataset

6Thursday, June 23, 2011

There is a Process

PublishConvertDescribeNameModelIdentify

Maintain

7Thursday, June 23, 2011

Preparation1.Leverage what exists

• Request a copy of the logical and physical model of the database(s)

• Obtain data extracts (i.e., databases and/or spreadsheets) or create data in a way that can be replicated.

8Thursday, June 23, 2011

Modeling the data2. Model data without context to allow for

reuse and easier merging of data sets

•Traditional DBAs organize data for specified Web services or applications.

•With LD, application logic does not drive the data schema, concepts, etc.

9Thursday, June 23, 2011

Modeling the data3.Look for real world objects of interest (e.g., people, places,

things, locations, etc.) and model them.

• Investigate how others are already modeling similar or related data.

• Look for duplication and normalize the data

• Use common sense to decide whether or not to make link

10Thursday, June 23, 2011

Modeling the data ...4. Connect data from different sources and authoritative

vocabularies (see list of popular vocabularies below).

• Use URIs as names for your objects

11Thursday, June 23, 2011

Modeling the data ...

• Put aside immediate needs of any application

• Don’t think about how an application will use your data

• Do think about time and how the data will change over time.

12Thursday, June 23, 2011

Convert, Publish & Maintain

5. Write a script or process to convert the data set repeatedly

6. Publish to the Web and announce it! (more details shortly)

7. Maintenance strategy (more details in the social contract at the end)

13Thursday, June 23, 2011

Take the plunge ... Be forgiving

• Simplistic data models can still be useful

• Better to make progress with something rather than do nothing because we cannot be comprehensive and complete

14Thursday, June 23, 2011

Take an iterative approach1. Review of modeling decisions

2. Review vocabularies chosen and developed

3. Modify/update data conversion scripts

4. Do a maintenance walk-through with real use cases

5. Show how to explore data with SPARQL and visualizations

6. Discuss a persistent identifier strategy (think PURLs)

15Thursday, June 23, 2011

Describe your

data

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Data stewards should....

• Make data accessible via the Web’s standard access mechanism, specifically http URIs

• Represent data in a common format, such as RDF/XML, Notation-3 (N3), Turtle, N-Triples, RDFa, and RDF/JSON

• Provide self describing data

17Thursday, June 23, 2011

Linked Data Formats• RDF/XML - RDF for XML pipelines

• Turtle - Human-readable RDF

• XHTML with GRDDL transformation

• XHTML with embedded RDFa

• RDF Schema - Describing structure

18Thursday, June 23, 2011

In a tart, smoothie or margarita ... berries

can be combined in different ways

19Thursday, June 23, 2011

The Social Contract ... The not so fine print

• LOD is a social contract to provide the public with information

• Follow best practices for modeling

• Carefully consider your URI strategy

• Ensure that your LOD remains available where you say it will be

• Publish voID description

• For a government agency ... a data policy is “a must”• specify data quality and retention, treatment of data thru

secondary sources, restrictions for use, frequency of updates, public participation, and applicability of this data policy

20Thursday, June 23, 2011

Announcing the

finished product!

21Thursday, June 23, 2011

•Inform the LOD developer community (linkeddata.org, W3 lists)

•Announce to search engines (RDFa hints, register to make accessible)•Publish human readable descriptions•Encourage interlinking•Publish schema as voID •Include SPARQL endpoint

22Thursday, June 23, 2011

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23Thursday, June 23, 2011

This presentation available at http://www.slideshare.net/bhylandwood/

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24Thursday, June 23, 2011