CDIF Core

Core interoperability specification for CDIF (Cross-Domain Interoperability Framework). The CDIF Core profile defines the mandatory and optional base properties for any CDIF metadata record, implemented using the schema.org vocabulary.

Specification

• CDIFCoreImplementationGuide.md — Complete documentation of all classes and properties for the CDIF Core profile, including required/optional properties, data types, and JSON-LD implementation guidance.
• cdifCoreStructuredSchema.json — JSON Schema (Draft 2020-12) for validating CDIF Core profile instances. Generated from the metadataBuildingBlocks source schemas.
• coreRules.shacl — SHACL validation shapes for CDIF Core. Copied from metadataBuildingBlocks/_sources/cdifProperties/cdifCore/rules.shacl and should be updated whenever the source changes.

Required properties

Every valid CDIF Core instance must include:

• @id — Resource identifier (IRI)
• @type — Must include schema:Dataset
• @context — JSON-LD context with schema, dcterms, dcat, prov prefixes
• schema:name — Descriptive name
• schema:identifier — Primary identifier (string or PropertyValue)
• schema:dateModified — Last update date (ISO 8601)
• schema:license OR schema:conditionsOfAccess — Rights/access information
• schema:url OR schema:distribution — Access to the resource
• schema:subjectOf — CatalogRecord with dcterms:conformsTo including https://w3id.org/cdif/core/1.0

Examples

The examples/ directory contains 40+ validated JSON-LD dataset examples that conform to the CDIF Core profile. These are records that do NOT use Discovery-level properties (spatialCoverage, temporalCoverage, variableMeasured) — records with those properties are in the Discovery repository.

Sources include:

Source	Count	Description
CDIF/ESIP/ODIS	9	Minimal, simple, and template examples
ADA	10	Core-stripped records from ADA test corpus
Kaggle	10	Iris, Netflix, Titanic, etc. — harvested from landing page JSON-LD
Dataverse	7	Harvard, Borealis, DANS, JHU — via Dataverse schema.org export API
PSDI DCAT	5	CSD, ChASe, AFLOW, etc. — converted from DCAT via DCAT/dcat_to_cdif.py
FEDEO	1	Satellite data collection with WebAPI distribution (OpenSearch)

All examples pass cdifCore JSON Schema validation.

JSON-LD Framing and Validation

FrameAndValidate.py frames a JSON-LD document against the CDIF Core schema and optionally validates it:

# Frame and validate
python FrameAndValidate.py examples/exampleCdifCoreMinimal.json --validate

# Frame and save output
python FrameAndValidate.py examples/exampleCdifCoreMinimal.json -o framed.json

# Use a different schema
python FrameAndValidate.py input.jsonld --validate --schema my-schema.json

The script uses cdifCore-frame.jsonld to frame JSON-LD documents into the expected property structure. Context prefixes from the input document are automatically merged into the frame, so domain-specific prefixes (e.g. ada:, xas:) work without being pre-declared in the frame.

Requirements: pyld, jsonschema (pip install pyld jsonschema)

SHACL Validation

coreRules.shacl contains SHACL shapes for validating CDIF Core instances. This file is copied from metadataBuildingBlocks/_sources/cdifProperties/cdifCore/rules.shacl and should be updated whenever the source changes.

Repository structure

├── CDIFCoreImplementationGuide.md  Classes and properties documentation
├── cdifCoreStructuredSchema.json    JSON Schema for validation
├── cdifCore-frame.jsonld           JSON-LD frame for document framing
├── FrameAndValidate.py             JSON-LD framing and JSON Schema validation
├── coreRules.shacl                 SHACL validation shapes (synced from metadataBuildingBlocks)
├── examples/                       40+ validated Core-only JSON-LD examples
├── ODIS/                           Archived ODIS type-specific templates and examples
└── LICENSE

Relationship to other CDIF repositories

• Discovery — Extends Core with spatialCoverage, temporalCoverage, variableMeasured, measurementTechnique, quality
• metadataBuildingBlocks — Source building block schemas, SHACL rules, and profile definitions
• validation — Framing, batch validation, conformance checking, harvesting, and DCAT conversion tools

License

See LICENSE.