Overview
ISO 21219-4:2019 - Intelligent transport systems (ITS): Traffic and travel information (TTI) via TPEG2 - Part 4 defines the UML to XML conversion rules for TPEG Generation 2 (TPEG2). The standard specifies how to convert TPEG application UML models into the tpegML format description, provides the XML (XSD) format definition for the abstract data types defined in ISO 21219-2, and sets out rules for converting compound data types. ISO 21219-4:2019 is intended as the normative basis for producing a tpegML annex in TPEG2 application and toolkit specifications.
Key technical topics and requirements
- tpegML schema definition: Guidance on namespace naming (http://www.tisa.org/TPEG/TPEGDataTypes_[MajorVersion]_[MinorVersion]), default/target namespace usage and schema import rules.
- XML Schema (XSD) settings: Recommendations that XSD elements and attributes be qualified, with elementFormDefault and attributeFormDefault set to “qualified”.
- XML format description structure: A required annex naming convention ([Specification Identification], tpegML representation) with subclauses for Introduction and Application data type definition.
- Abstract data types and ranges: XML definitions for the abstract data types from ISO 21219-2 and explicit handling of XML data type ranges.
- Tables and enumerations: Rules for mapping TPEG standard tables, application tables (> stereotypes) and switching tables into XML.
- Stereotype handling: Conversion rules for > types, including TPEG application externals and non-TISA external references (XML schema or binary).
- Compound data types: Detailed conversion rules for classes, root elements, attributes, and specializations/abstract classes (see clauses such as 5.10 and its subrules).
- Normative references: Alignment with ISO 21219-2 (UML modelling rules), ISO 21219-5 (service framework), and ISO 8601 (date/time representation).
Practical applications and users
ISO 21219-4:2019 is primarily used to enable reliable, interoperable XML representations of TPEG2 traffic and travel information. Typical users include:
- ITS application developers and system integrators creating TPEG2 content pipelines and services.
- Data modelers and UML architects converting UML models into validated tpegML schemas.
- Tool and platform vendors implementing automated UML→tpegML conversion, schema generation and validation.
- Service providers and broadcasters publishing traffic and travel information in XML-based exchange formats.
- Standards and compliance teams ensuring TPEG2 artifacts conform to the required schema, namespaces and conversion rules.
Benefits include improved interoperability, consistent schema generation, easier validation of TTI content, and support for automated toolchains that convert UML models (XMI) into reusable tpegML XSDs.
Related standards
- ISO 21219-2 - TPEG2 UML modelling rules (abstract data type definitions referenced by this part)
- ISO 21219-5 - TPEG2 Service Framework (tpegML schema import guidance)
- ISO 8601 series - Date and time representations used in XML data types
Keywords: ISO 21219-4:2019, TPEG2, UML to XML conversion, tpegML, intelligent transport systems, traffic and travel information, XML schema, XSD, abstract data types.