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PSDI Resource Catalogue Description

Summary​

The PSDI catalogue is part of the metadata for the Physical Sciences Data Infrastructure (PSDI) and it is a resource catalogue that describes resources, data, services, tools and guidance which are made available through it.
The latest released version of it is available at: https://metadata.psdi.ac.uk/psdi-dcat.jsonld. This document outlines background reading, guidance and guidelines for anyone who wants to use thi smetadata, contribute to it or wants to describe a new resource which will become part of it.

Purpose of PSDI resource catalogue​

  • it contents are used to populate the PSDI What We Provide resource catalogue
  • discoverability and interpretation of PSDI applications and components for machines and indexes

What is included?​

Top-level description of PSDI resource catalogue and the resources, data, services, tools and guidance that it describes

Background reading​

  1. Data Catalog Vocabulary (DCAT) - Version 3
  2. JSON-LD Best Practices
  3. DCAT for Beginners

Nomenclature and overall structure​

The output is a Data Catalog Vocabulary (DCAT) - Version 3 vocabulary in JSON-LD format.

This has been implemented as a top-level PSDI resource catalogue with id [psdiCat:resourceCatalogue] which also contains nested catalogues - each of which corresponds to a "resource theme" as defined by PSDI vocabulary (not to be confused with the DCAT definition of "resource"):

  • [dcat:Catalog] with id [psdiCat:resourceCatalogue] defines the entire PSDI resource catalogue as a whole

Note that:

  • the definition for each of these terms in PSDI is defined in machine-readable form in PSDI vocabulary and in human-readable form in PSDI Terminology
  • resource theme corresponds to the dcat definition of [dcat:Catalog] (not [dcat:Resource] as you might expect, because this class should not be directly defined in a dcat catalogue according to DCAT for Beginners ). Note that due to the nested nature of PSDI we do have some instances of [dcat:Catalog] which don't have a [dcat:Dataset] within them
  • data corresponds to the dcat definition of [dcat:Dataset]
  • service broadly corresponds to the dcat definition of [dcat:DataService] with the slight broadening of its DCAT definition that these are not always associated with a specific dataset, and they sometimes process data, rather than just making it accessible.
  • in addition to these two sub-classes of the [dcat:Resource] class, we have made two other extensions to the [dcat:Resource] class to capture tools and guidance. The DCAT description of these classes and their properties are described in psdi-dcat-ext.jsonld and their definition in the context of PSDI is in tool and guidance respectively. These also inherit the properties of their parent [dcat:Resource] class too.
  • we refer to data, service(s), tool(s) and/or guidance(s) collectively as resources
  • properties specified at the resource theme level describe all outputs from this research (data, services, tools and/or guidance)
  • properties in the data, service, tools and guidance objects are relevant to these items only (values are inherited from the resource above if blank)

PIDs (Persistent Identifiers)​

The following convention has been used for persistent identifiers of items within the PSDI resource catalogue:

  • all identifiers are within the ["psdiDcat:"] namespace where ["psdiDcat": "http://metadata.psdi.ac.uk/psdi-dcat/"]
  • ids defined in this vocabulary are not in general human readable. When the namespace prefix "psdiDcat" of [@ids] within this jsonld are expanded their iris take the form: {http://} + {metadata.psdi.ac.uk/} + {psdi-dcat} + [/] + {type/} + {id} (e.g. http://metadata.psdi.ac.uk/psdi-dcat/data/07d83ee6-bad9-4c23-abea-ac70745b0803). See PSDI Metadata General Guidelines > PIDs (Persistent Identifiers) for more general information.
  • pids in the PSDI catalogue are generally opaque strings that are 36 characters long which are randomly generated GUIDs (using UUIDv4) -using the python uuid class e.g. [python -c "import uuid; print(str(uuid.uuid4()))"] or an online UUIDv4 generator
  • one exception to this are ids for data in the "OPTIMADE Data Providers" which have the @id format [{psdiDcat:data/optimade-} + provider_id + {-} + dataset_id] (e.g. psdiDcat:data/optimade-alexandria-alexandria-pbesol) and their distributions which have the @id format [{psdiDcat:distribution/optimade-} + provider_id + {-} + dataset_id] + {-i} (e.g. psdiDcat:distribution/optimade-alexandria-alexandria-pbesol-i)

Fields​

Versioning​

  • After making changes to this file the following top-level metadata fields for the file should be reviewed or updated:
    • [dcat:version]
    • [adms:status]
    • [adms:versionNotes]
    • [dcterms:issued]
    • [dcterms:modified]
    • [spdx:checksum]

Validation​

See general JSON-LD metadata validation outlined in PSDI Metadata Checking Guidelines. Additional validation specific to this profile:

About this page
  • Creator: Aileen Day
  • Last modified date: 2025-04-09