Overview
ISO/IEC 21972:2020 - Information technology - Upper level ontology for smart city indicators - defines an Indicator Upper Level Ontology (IULO) to represent smart city indicator definitions and the data used to derive them. Designed for use with Semantic Web technologies (OWL 2), the standard provides a general ontology pattern to make indicator semantics precise, machine‑readable and interoperable across datasets, tools and cities.
Key SEO terms: ISO/IEC 21972:2020, IULO, smart city indicators, ontology, OWL, semantic interoperability, indicator definitions.
Key topics and technical requirements
The standard establishes general principles and guidelines rather than prescriptive data models. Notable technical topics and requirements include:
- Core concepts and properties: definitions for concepts such as indicator, population, cardinality, and properties like cardinality_of and parameter_of_var for relating concepts.
- Time modeling (Clause 6): guidelines for representing temporal extents and temporal properties of indicators (uses Time Ontology concepts).
- Quantities and units (Clauses 7–8): formal treatment of quantities, units of measure and indicator quantities to ensure numeric semantics are explicit and comparable.
- Statistics (Clause 9): representation of statistical constructs needed for indicator computation and validation.
- Populations (Clause 10): modeling membership extent, spatial and temporal extent, and measured variables for target populations used in indicators.
- Formal specification and examples (Clauses 7–11): OWL 2‑based formalization and an illustrative example to guide implementation.
- Interoperability approach: intended to map local data models to the IULO to achieve semantic interoperability without replacing domain‑specific models.
Normative references include ISO 37120, ISO 4217, ISO 80000 and W3C Time Ontology. The IULO intentionally excludes theme‑specific domain concepts (e.g., education, transport) and metadata such as provenance.
Practical applications and users
ISO/IEC 21972:2020 supports practical use cases:
- Indicator‑independent calculation engines: compute indicators automatically from base data using machine‑readable definitions.
- Diagnosis and root‑cause analysis: trace how indicator values were derived and detect inconsistencies across time/place.
- Data integration and semantic interoperability: map municipal, regional or national datasets to a common semantic model.
- Open data publishing: publish indicator definitions and values in a form usable by apps, researchers and policy makers.
Primary users include city planners, ICT vendors, data integrators, open‑data developers, standards bodies and researchers working on smart city analytics.
Related standards
- ISO 37120:2018 - Indicators for city services and quality of life (normative reference)
- ISO 4217 - Currency codes
- ISO 80000 - Quantities and units
- W3C Time Ontology and OWL 2 - Semantic Web foundations
Adopting ISO/IEC 21972:2020 helps cities and technology providers create unambiguous, computable indicator definitions-enabling reliable benchmarking, automated analytics and better data‑driven urban decision making.