Module 5

Vocabulary Reuse

Match concepts across vocabularies and track provenance correctly.

Why Reuse Vocabularies?

Building vocabularies from scratch is expensive. If an authoritative vocabulary already exists — from a standards body, government agency, or international registry — you can reuse it rather than duplicating work. Reuse creates semantic bridges between datasets that use different terms for the same concepts.

Reuse Patterns

Verbatim — use the existing vocabulary unchanged. Just reference its IRI.
Adoption — import some or all concepts into your vocabulary, retaining original IRIs and definitions.
Customise — adopt concepts and make minor label/note changes; acknowledge modifications at concept and scheme level.
Matching — keep your vocabulary separate but declare relationships to concepts in the other.

Provenance: Where did this concept come from?

When you adopt or customise concepts from another vocabulary, you must record where they came from using W3C PROV-O properties:

provenance.ttl

PREFIX : <https://linked.data.gov.au/def/road-travel-direction/>
PREFIX cs: <https://linked.data.gov.au/def/road-travel-direction>
PREFIX regstatus: <linked.data.gov.au/def/reg-status/>
PREFIX dcterms: <http://purl.org/dc/terms/>
PREFIX icsm: <https://linked.data.gov.au/org/icsm>
PREFIX owl: <http://www.w3.org/2002/07/owl#>
PREFIX prov: <http://www.w3.org/ns/prov#>
PREFIX qsi: <https://linked.data.gov.au/org/qsi>
PREFIX rdfs: <http://www.w3.org/2000/01/rdf-schema#>
PREFIX sdo: <https://schema.org/>
PREFIX skos: <http://www.w3.org/2004/02/skos/core#>
# add PREFIX srti: for the imported concept vocabulary
PREFIX srti: <http://cef.uv.es/lodroadtran18/def/transporte/dtx_srti#>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>

# Add concept from external concept scheme
srti:clockwise a skos:Concept;
    skos:prefLabel"Both directions"@en ;
# add definition verbatim from source
    skos:definition"Clockwise."@en ;
    prov:wasDerivedFrom srti:#clockwise ; 
# add scheme membership and indicate top concept if the imported concept has no skos:broader in the cs:
    skos:inScheme cs: ;
    skos:topConceptOf cs: 
.
    
cs:    a skos:ConceptScheme;
    dcterms:created"2023-05-30"^^xsd:date ;
    dcterms:creator qsi: ;
# Date modified MUST be incremented
    dcterms:modified"XXXX-XX-XX"^^xsd:date ;
    dcterms:publisher icsm: ;
# Version information MAY be incremented
    owl:versionInfo"1.0" ;
    skos:definition"This vocabulary describes the travel direction assigned to a section of a road."@en ;
    skos:hasTopConcept
        :bi-directional ,
# Add new Concept "clockwise":
        srti:clockwise ,
        :none ,
        :one-way ,
        :one-way-against-vector ,
        :one-way-with-vector ,
        :unknown ;
# History note extended
    skos:historyNote"This vocabulary was created by the Queensland Spatial Information services and import a concept from LOD SRTI DATEX II" ;
    skos:prefLabel"Road Travel Direction"@en
.

SKOS Match Properties

When matching, you choose a relationship that reflects how similar the concepts are:

Property	Meaning	When to use
`skos:exactMatch`	Concepts are interchangeable in all contexts	High confidence equivalence across vocabularies, ideally with agreement between vocabulary managers
`skos:closeMatch`	Concepts are very similar and may be interchangeable	Strong resemblance without authorisation or agreement between vocabulary managers
`skos:broadMatch`	The other concept is more general	Your concept fits inside the external concept
`skos:narrowMatch`	The other concept is more specific	Your concept is a supertype of the external one
`skos:relatedMatch`	Thematic association across vocabularies	Related but not hierarchically linked

Exercise — Match concepts across vocabularies

Select one concept from each vocabulary, pick a match type, then click Add Match. Your matches will appear as Turtle below.

Our Vocabulary
Bushfire Risk Levels

Match Type

External Vocabulary
ISO 22324 Warning Colours

Reusing Non-Semantic Vocabularies

Building a vocabulary from scratch is an easy win for ensuring it is well-formed and presented. Existing vocabularies published in other contexts may not be so well-formed! Those you find — including via vocabulary registries — vary in their conformance with data standards such as RDF and SKOS, before you even consider quality standards like VocPub and qSKOS. A few challenges to weigh up:

Unstructured

The vocabulary is well presented but not machine-readable — a PDF or HTML page. Its terms may imply properties and relationships, but those properties are not themselves machine-readable. It needs to be scraped and cleaned, then transformed into an RDF format a SKOS editing tool can open — see the Curating Labels & Definitions module.

Token IDs

The vocabulary uses non-semantic or token identifiers — such as 123 or AC123 — that are not unique out of context and do not resolve on the web. For provenance and tracking, use such an identifier as the suffix of an IRI in your vocabulary. Optionally, retain the original as a skos:notation "AC123". You will still need to construct a full IRI — see Unidentified below.

Token identifier	Constructed IRI
`123`	`https://vocabs.mydomain.org/123`
`AC123`	`https://vocabs.mydomain.org/AC123`

Unidentified

The vocabulary has labels but no identifiers, so new IRIs must be constructed. Where there are no identifiers for concepts at all, mint your own — but make them opaque, using a scheme like UUID (generated with a web service).

Minting IRIs

Do not base IRIs on another organisation's domain without first consulting them. Either use the example namespace http://example.com[vocab/ID], or a domain you own or control.

Module 4