Common Data Types

Several JSON-LD encoding patterns recur across the CDIF profiles. They are defined once here and referenced from the individual profile pages. All property names use namespace prefixes declared in each document’s @context (schema:, skos:, dcterms:, cdi:, xsd:, etc.).

Object Reference¶

A reference to another node by its @id, used to link to an object defined elsewhere in the same document, in another CDIF document, or externally. An object reference carries no other properties — it is resolved by matching its @id to the full node definition.

• JSON: {"@id": "uri for target"}

• Scope note: An ‘object reference’ indicates that a property value is specified with a URI rather than an inline object. The @id value must be a resolvable identifier that yields a JSON object of the type the property expects. For some elements the target is an @id node defined elsewhere in the same document; otherwise it should be a resolvable HTTP URI for an external resource.

LanguageTaggedValue¶

An RDF literal with a language tag, serialized as a JSON-LD value object.

• JSON: {"@value": "Natural Solid Material", "@language": "en"}

• Scope note: @value is the text content; @language is a BCP 47 language tag (e.g. en, fr, de, sv). Use an array of LanguageTaggedValue objects to provide a label or text in multiple languages.

DefinedTerm¶

A schema:DefinedTerm represents a concept drawn from a controlled vocabulary, providing a human-readable name together with a resolvable identifier and a link to the vocabulary that defines it.

• JSON:

  {
    "@type": ["schema:DefinedTerm"],
    "schema:name": "{string}",
    "schema:identifier": "{URI}",
    "schema:inDefinedTermSet": "{URI}",
    "schema:termCode": "{string}"
  }

• Scope note: Use a DefinedTerm (rather than a plain string) whenever a value comes from a known vocabulary. schema:name is the label, schema:identifier the concept URI, schema:inDefinedTermSet the vocabulary URI, and schema:termCode an optional short code. A skos:Concept may be used instead where a fuller SKOS description is available.

xsdDataType¶

The XML Schema datatype that constrains the lexical form of a value, given as a CURIE in the xsd: namespace.

• JSON: "xsd:double" (e.g. xsd:string, xsd:integer, xsd:double, xsd:date, xsd:dateTime, xsd:boolean, xsd:anyURI)

• Scope note: Identifies the primitive datatype used to interpret values, drawn from the XML Schema built-in datatypes. Use where a variable or value domain needs an unambiguous machine-readable datatype.

PropertyValue (variableMeasured)¶

The Discovery-profile shape for a schema:variableMeasured item: a schema:PropertyValue describing one variable in a dataset. The Data Description profile extends this base with additional CDIF properties.

• JSON:

  "schema:variableMeasured": [{
    "@type": ["schema:PropertyValue"],
    "@id": "astm:var0011",
    "schema:propertyID": ["pato:PATO_0000025", "astm:prop/0405"],
    "schema:name": "hostMineral",
    "schema:description": "..."
  }]

• Scope note: Base properties available on every variableMeasured item: @id, schema:name, schema:description, schema:alternateName, schema:propertyID (URI(s) for the represented concept — the semantic linkage for the variable’s meaning), schema:measurementTechnique, schema:unitText, schema:unitCode, schema:minValue, schema:maxValue, schema:url. Follows the ESIP Science on Schema.org recommendation.

PropertyValue (identifier)¶

A schema:PropertyValue used to express a structured identifier when a plain resolvable URI does not make the identifier scheme or resolution process clear.

• JSON:

  {
    "@type": ["schema:PropertyValue"],
    "schema:propertyID": "https://registry.identifiers.org/registry/doi",
    "schema:value": "10.5683/SP2/TTJNIU",
    "schema:url": "https://doi.org/10.5683/SP2/TTJNIU"
  }

• Scope note: The ESIP Science on Schema.org guidance recommends serializing identifiers as schema:PropertyValue. CDIF suggests using this approach only for identifiers whose URI does not make the authority clear or whose resolution process is not well known; otherwise a simple URI string is sufficient.