The NERC DataGrid Vocabulary Server: The NERC DataGrid Vocabulary Server: an operational system with distributed ontology potentialan operational system with distributed ontology potential

Roy Lowry

British Oceanographic Data Centre

GO-ESSP 2008, Seattle, September 2008GO-ESSP 2008, Seattle, September 2008

Presentation SummaryPresentation Summary

What we’ve got

How to use it

What’s wrong with it?

What we’re doing about it

What’s in it for CF?

What We’ve GotWhat We’ve Got Server Contents (2008-08-21)

112 public lists 122603 concepts 78123 mappings (RDF triples)

Server Usage 2008 (to 2008-08-21)

2233803 total hits (2000000 of these attributable to robots)

37462 vocabulary catalogue hits 50458 vocabulary list downloads 2085 vocabulary mapping queries

In summary a heavily populated, heavily used system

How to Use ItHow to Use ItThere are four ways to access

vocabulary content

Term and list URLs

HTTP-POX web service calls

SOAP web service calls

Interface clients

How to Use ItHow to Use It Term and list URLs

Any list may be accessed using a URL of the form http://vocab.ndg.nerc.ac.uk/list/list_id/list_version

Delivers the list, without mappings, as a SKOS XML document

Any term my be accessed using a URL of the form http://vocab.ndg.nerc.ac.uk/term/list_id/list_version/term_id

Delivers the term, including all mappings, as a SKOS XML document

How to Use ItHow to Use It<?xml version="1.0" ?>

- <rdf:RDF xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#" xmlns:skos="http://www.w3.org/2004/02/skos/core#" xmlns:dc="http://purl.org/dc/elements/1.1/">

- <skos:Concept rdf:about="http://vocab.ndg.nerc.ac.uk/term/P021/25/PHYC">

  <skos:externalID>SDN:P021:25:PHYC</skos:externalID>

  <skos:prefLabel>Phycobolin pigment concentrations in the water column</skos:prefLabel>

  <skos:altLabel>WC_PhycobolPig</skos:altLabel>

  <skos:definition>Concentration of phycobolin group pigments such as phycocyanin and phycoerythrin in the water column</skos:definition>

  <dc:date>2008-03-11T11:56:27.531+0000</dc:date>

  <skos:minorMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P041/4/G905" />

  <skos:broadMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P031/8/B035" />

  <skos:broadMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P041/4/G378" />

  <skos:broadMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P051/0/002" />

  <skos:broadMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P051/0/014" />

  <skos:narrowMatch rdf:resource="http://vocab.ndg.nerc.ac.uk/term/P011/79/PHYCSPP4" />

  </skos:Concept>

  </rdf:RDF>

How to Use ItHow to Use It HTTP-POX service calls

Any API method may be invoked using an HTTP get call

Lists and terms specified in the get call parameters as URLs

Delivers an appropriate XML document (BODC-designed schema)

Documentation at http://www.bodc.ac.uk/products/web_services/vocab/methods.html

SOAP web service calls

WSDL may be found at http://vocab.ndg.nerc.ac.uk/ Same output and documentation as HTTP-POX

How to Use ItHow to Use ItInterface clients

Maris client set up for SeaDataNet at http://seadatanet.maris2.nl/v_bodc_vocab/welcome.aspx

BODC clients at http://vocab.ndg.nerc.ac.uk/ cover more vocabularies if interests extend beyond SeaDataNet

How to Use ItHow to Use ItTypical Maris client output

How to Use ItHow to Use It In SeaDataNet vocabulary terms are

included in data and metadata as URNs

These have the form:

SDN:list_id:list_version:term_id, e.g.

SDN:P021:23:TEMP SDN:P021::TEMP (for current version)

URNs resolve to URLs by simple string substitution (service to do this planned)

URLs may be used to obtain the term identifiers, labels and mappings in an XML document

What’s Wrong With It?What’s Wrong With It?

Historic version serving not implemented

Current version served whatever version is requested

Predicates (SKOS mappings) semantically limited

More suited to a thesaurus rather than an ontology

Richer set in the triple store, but cannot be served without WSDL changes

What’s Wrong With It?What’s Wrong With It?

Vocabularies not labelled with content governance authority

Mappings restricted to concepts within the server

If a vocabulary is to be included in a mapping then it must be loaded in the server

Not exactly Semantic Web!

What We’re Doing About ItWhat We’re Doing About It

Historic version serving not implemented

Necessary SQL now written so functionality will be incorporated into the next release

Predicates (SKOS mappings) semantically limited

Collaboration with Sean Bechhofer (Manchester Computer Science) to design better SKOS documents for server payload

What We’re Doing About ItWhat We’re Doing About It

Vocabularies not labelled with content governance authority

On the list of things to do for version 1.2

Mappings restricted to concepts within the server

Developing interoperable server in collaboration with ICES

Triple store structural redesign under consideration

What We’re Doing About ItWhat We’re Doing About It

In practice

V1.2 planned for the end of the year

Historic version serving

Vocabularies labelled with content governance

V2.0 date not yet fixed

Linkage to external resources

Improved SKOS document payload

What’s in it for CF?What’s in it for CF?

Currently serve Standard Names and Cell Methods

Synchronised with CF site (Alison provides update material)

Mappings maintained to SeaDataNet (BODC) and GCMD vocabularies

Support for representation of Standard Names as URLs that may be mapped and used as URNs

That’s All FolksThat’s All Folks

Thank you for your Attention

Any Questions?