Overview
ISO 21597-2:2020 - "Information container for linked document delivery - Exchange specification - Part 2: Link types" - defines a standardized set of link types to describe semantic relationships between documents and document elements stored inside an ISO 21597 container. Part 2 extends the generic linking model of ISO 21597-1 by specifying nine human-interpretable link types (the Extended Linkset ontology) to add metadata about identity, dependency, comparison and grouping without altering the container payload.
Key technical topics and requirements
- RDF(S)/OWL-based ontologies: All ontologies in conforming containers must use RDF, RDFS and OWL constructs and be serialized in RDF/XML or an equivalent RDF serialization.
- Extended Linkset ontology: Part 2 defines nine link types (see list below) in Annex C. These are objectified link concepts so they can carry annotations and metadata.
- Nine primary link types (specified in clause 5):
- Identity
- Conflict
- Alternative
- Specialization
- Aggregation
- Membership
- Replacement
- Elaboration
- Control
- Link categories: Link types are specialized from two generic classes - ls:DirectedBinaryLink and ls:Directed1toNLink - with explicitly defined inverses for one-to-many relationships.
- Annotation-only semantics: Links provide human-interpretable commentary and metadata; the standard intentionally avoids prescriptive machine reasoning or inferring deeper semantics from links.
- Conformance and validation: Clause 6 sets conformance requirements. Informative annexes include use cases, SHACL validation guidance (Annex B) and the normative Extended Linkset ontology (Annex C).
Practical applications and who would use this standard
ISO 21597-2 is targeted at organizations and professionals managing complex, interrelated document sets-particularly in construction and BIM workflows:
- BIM managers, architects, engineers, contractors - to annotate relationships between drawings, specifications and models.
- Document controllers and information managers - to provide clear, standardized metadata about conflicts, replacements or alternatives across document versions.
- Software vendors and integrators - to implement container exchange tools, RDF/OWL-based linksets and SHACL validation for automated checks.
- Facility managers and asset owners - to interpret provenance, dependencies and aggregation of documents delivered as a single container.
Benefits include clearer document relationships, better information delivery in multi-format containers, and interoperable metadata for exchange workflows.
Related standards and keywords
- Related: ISO 21597-1:2020 (Container structure and generic links)
- W3C specs referenced: RDF 1.1, RDFS, OWL 2, RDF/XML
- SEO keywords: ISO 21597-2, link types, information container, linked document delivery, Extended Linkset, RDF, OWL, RDFS, BIM metadata, document linking, SHACL validation.
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