Overview
ISO 19112:2019 - Geographic information: Spatial referencing by geographic identifiers defines a conceptual schema for describing spatial references that use geographic identifiers (labels or codes such as place names, postcodes or feature identifiers) rather than direct coordinates. The standard specifies a general model for spatial reference systems based on location classes, a consistent conceptual scheme for gazetteers, and a mechanism to record complementary coordinate references. It applies primarily to digital geographic data but can be extended to maps, charts and textual documents.
Key topics and requirements
- Conceptual schema (UML): The standard provides a UML-based model for:
- SpatialReferenceSystemUsingGeographicIdentifiers - a system composed of one or more LocationClass definitions.
- LocationClass and Location - classes that describe types of places and their instances.
- Gazetteer and GeographicIdentifier - consistent structures for registers of location instances and their identifiers.
- Conformance classes:
- Spatial reference system using geographic identifiers (requirements in Clause 6).
- Gazetteer (requirements in Clause 7).
- Metadata and attributes: References to metadata and extent types from ISO 19115-1 (e.g., MD_Identifier, EX_Extent) are used to describe domain of validity and identifiers.
- Hierarchy and relationships: Location classes can be aggregated or disaggregated to form hierarchies (e.g., country → region → town → property).
- Complementary coordinate references: While coordinates are covered by ISO 19111, ISO 19112 allows recording complementary coordinate references where useful.
- Test suites and examples: Annex A contains abstract test suites; Annexes B–D provide informative examples and backward compatibility guidance.
Applications and who uses it
ISO 19112:2019 is practical for organizations that create, publish or consume geographic information relying on place identifiers rather than coordinate tuples:
- National mapping and cadastral agencies building standardized gazetteers.
- GIS professionals designing spatial reference systems based on administrative units, postal codes, or feature identifiers.
- Data custodians and metadata specialists documenting domainOfValidity, identifier schemes and register structures.
- Software vendors and developers of location-based services, geocoding and address management systems.
- Standards bodies and integrators ensuring interoperability between datasets that use indirect (identifier-based) spatial references.
Related standards
- ISO 19111 - Spatial referencing by coordinates (complementary coordinate definitions)
- ISO 19115-1 - Metadata (MD_Identifier, EX_Extent)
- ISO 19135-1 - Procedures for item registration (gazetteer as a Register)
- ISO 19160-1 - Addressing (related addressing models)
ISO 19112:2019 helps ensure consistent, interoperable use of place names and codes across digital geospatial datasets, improving discoverability, integration and practical use of geographic information.
