Overview
ISO 21962:2003 - titled Space data and information transfer systems - Data entity dictionary specification language (DEDSL) - PVL syntax - defines the Parameter Value Language (PVL) requirements used to create a Data Entity Dictionary (DED) for space data products. Adopted from CCSDS 647.2-B-1, this international standard provides a machine-processable PVL mapping of the DEDSL abstract syntax so that semantic metadata can be expressed, exchanged, and interpreted consistently across space agencies and communities.
Key topics and technical requirements
- PVL syntax for DEDSL: Specifies how DED abstract syntax maps to PVL constructs to enable formal, processable dictionary files.
- Dictionary attributes: Defines required and optional attributes for a DED (identification, definitional, relational, representational, administrative).
- Data entity attributes: Specifies attribute blocks and descriptors used to describe data entities (identifiers, definitions, relationships).
- User-defined attributes: Mechanism for community- or project-specific attribute descriptors, including rules for value types, default values, and occurrence limits.
- Conformance levels: Two levels (notation compliance and full compliance) to guide implementations and assess interoperability.
- Reserved keywords and examples: Lists reserved PVL keywords and provides annex examples to illustrate correct DEDSL/PVL usage.
- Document structure and mappings: Contains mappings between DEDSL types and PVL types, block structures, and implementation guidance.
Practical applications
- Enables creation of standardized metadata dictionaries that accompany space data products (remote sensing, space physics, archival data).
- Facilitates automated parsing, validation, and ingestion of data product metadata by software tools and data repositories.
- Supports community-wide dictionaries for Earth observation, planetary missions, archives, and other space science domains to ensure consistent semantics.
- Helps organizations mandate and exchange dictionary contents to improve data interoperability, discoverability, and long-term preservation.
Who should use this standard
- Data producers (space missions, instrument teams) constructing formal DEDs for distribution with data products.
- Data users and integrators who need to interpret or ingest metadata from external providers.
- Software developers building tools for metadata validation, cataloging, and automated processing.
- Standards bodies and program managers establishing community- or agency-level dictionary conventions to harmonize metadata.
Related standards
ISO 21962:2003 is part of the CCSDS/ISO space data standards family. Relevant referenced documents include CCSDS 647.2-B-1 (the originating recommendation) and related ISO/CCSDS standards cited in the publication (for example, ISO 21961, ISO 14961, ISO 12175 and ISO/IEC 8859-1 as referenced encoding). These related standards complement DEDSL/PVL for broader metadata, encoding, and interchange requirements.
Keywords: ISO 21962, DEDSL, PVL syntax, data entity dictionary, space data, CCSDS, metadata, interoperability, Earth observation.