Overview
ISO/TS 19139-1:2019 - Geographic information - XML schema implementation - Part 1: Encoding rules - defines a rules-based method for deriving XML Schema (XSD) encodings from UML conceptual schemas that describe geographic resources and metadata. Produced by ISO/TC 211, the Technical Specification targets XML implementations of metadata (not feature application schemas - see ISO 19136). Its goal is consistent, interoperable XML encodings for ISO geographic metadata standards.
Key topics and technical requirements
- Scope and conformance: Rules apply to UML profiles commonly used in ISO/TC 211 and require conformance to the encoding constraints and test-suite (Annex A).
- Encoding rules (Clause 7): Defines how UML elements map to XML constructs, including:
- XML Class Type (XCT), XML Class Global Element (XCGE), XML Class Property Type (XCPT).
- Stereotypes such as >, >, > to drive XSD generation.
- Special-case encodings: Handling of abstract classes, inheritance and subclassing, enumerations, CodeList encodings, unions, meta-classes and externally identified implementations.
- Requirements for encoding (Clause 6): Rule-based, quality considerations, web implementation guidance, use of external XML implementations, and polymorphism support.
- Modularity and reuse (Clause 9): Mapping UML packages to XML namespaces and schema packages; guidelines for decoupling to support reuse and modular XML schemas.
- Namespaces and interoperability: Alignment with W3C XML, XML Schema (Part 1 & 2), XLink and GML namespaces to ensure consistent element/attribute naming.
- Supporting material: Annex B discusses backward compatibility; bibliography and normative references include ISO 19118, ISO 19136, and W3C recommendations.
Applications and users
Who benefits:
- GIS standards authors and ISO/TC 211 working groups deriving XML encodings for metadata standards (e.g., ISO 19115-1, ISO/TS 19115-3, ISO/TS 19157-2).
- Software vendors, system integrators and data custodians implementing metadata exchange, validation and interoperability using XML/XSD and GML.
- Metadata modelers and architects transforming UML conceptual models into validated XML schemas for catalogs, web services, and data portals.
Practical value:
- Produces consistent, machine‑readable schema for metadata exchange.
- Enables schema validation, automated tool generation, and reduced ambiguity across implementations.
- Facilitates modular schema design and reuse across ISO geographic information standards.
Related standards
