DCAT-US Schema v3.0 Catalog fields

Overview

Field-level reference for the DCAT-US v3.0 Catalog class. A Catalog is the top-level container for an agency’s data inventory.

Source

data.gov

Category

Keywords

DCAT,

Details

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Overview

The Catalog class is the top-level container for an agency’s data inventory. Your agency’s data.json file is an instance of a DCAT-US Catalog. It holds the array of Dataset records and, in v3.0, can also reference DataService records. Required field in v3.0: A Catalog must contain at least one Dataset. —

Moving from DCAT-US v1.1 to v3.0

If your agency is upgrading from v1.1, your catalog structure carries forward with minimal changes. The dataset array works the same way. The main differences are: @context is no longer a catalog field, conformsTo now uses a Standard object rather than a plain URI string, and describedBy has been removed. Several new optional fields are available, including service for registering APIs and title and description for the catalog itself. A valid v3.0 catalog requires only one thing: a dataset array containing at least one Dataset record. Everything else is optional at the catalog level. However, adding @id, @type, conformsTo, title, modified, and publisher at the catalog level is strongly recommended as it makes your catalog self-describing and helps harvesters like Data.gov identify and process it correctly. Your agency’s data.json file is an instance of the Catalog class. The file hosted at agency.gov/data.json is what Data.gov harvests. Setting @id to the URL of your data.json file itself is the recommended way to give your catalog a persistent identifier. —

Changes from v1.1

v1.1 Field Status in v3.0 Action
@context Removed Remove from your catalog file.
conformsTo as plain string URI Now a Standard object Change to {"@type": "Standard", "title": "DCAT-US 3.0", "identifier": "https://resources.data.gov/dcat-us/3.0.0"}
describedBy Removed at catalog level Remove from your catalog file. The Standard object in conformsTo serves this purpose.
dataset Unchanged No change required. Dataset objects inside must be updated to v3.0 format.

New in v3.0: title, description, publisher, contactPoint, keyword, spatial, language, license, rights, issued, modified, service, record, themeTaxonomy, catalog

Field Why it matters
@id Uniquely identifies your catalog. Use the URL of your data.json file itself — for example, https://www.agency.gov/data.json. This helps harvesters like Data.gov track your catalog as a persistent resource.
@type Tells harvesters this is a DCAT Catalog. Should be dcat:Catalog.
conformsTo Identifies which version of DCAT-US your catalog uses. For v3.0 use a Standard object: {"@type": "Standard", "title": "DCAT-US 3.0", "identifier": "https://resources.data.gov/dcat-us/3.0.0"}
title A human-readable name for your catalog. Makes your catalog discoverable as a named resource rather than just a file.
modified The most recent date your catalog content changed. Harvesters use this to detect when to re-index your catalog. Keep it updated whenever datasets are added, removed, or changed.
publisher Identifies your agency as the catalog owner. Use an Agent object: {"name": "Example Federal Agency"}.
language Declares the language of your catalog metadata. Use two-letter ISO 639-1 codes — for example, ["en"] for English.

Catalog fields

Field Required Type Description
dataset Mandatory array of Dataset objects The list of datasets in this catalog. See Dataset fields.
@id Optional string (IRI) A unique identifier for the Catalog. Recommended: use the URL of the data.json file itself. Example: https://www.agency.gov/data.json.
@type Optional string Should be dcat:Catalog.
conformsTo Recommended Standard object A Standard object identifying the schema version this catalog conforms to. For v3.0 use: {"@type": "Standard", "title": "DCAT-US 3.0", "identifier": "https://resources.data.gov/dcat-us/3.0.0"}
title Optional string A human-readable title for the catalog.
description Optional string A human-readable description of the catalog and its contents.
issued Optional string (ISO 8601) Date the catalog was formally issued.
modified Optional string (ISO 8601) Most recent date the catalog was modified. Keep this updated — harvesters use it to detect changes.
language Optional array of strings Language(s) of the catalog. Use two-letter ISO 639-1 codes (e.g., en, es, fr).
license Optional string (URL) License for the catalog as a whole. See Open Licenses.
rights Optional array of strings Rights information for the catalog.
spatial Optional array of Location objects Spatial coverage of the catalog. References the Location class.
contactPoint Optional array of Kind objects Contact points for the catalog. References the Kind class.
keyword Optional array of strings Keywords or tags describing the catalog.
publisher Optional Agent object The publishing entity for this catalog. References the Agent class.
catalog Optional array of Catalog objects Related catalogs linked from this one — for example, sub-agency catalogs within a department-level catalog. The Department of Commerce could maintain a top-level catalog that references separate catalogs from the Census Bureau, NOAA, NIST, and other bureaus. Each sub-agency continues to maintain its own data.json and the department-level catalog links to them via this field.
service Optional array of DataService objects New in v3.0. DataService resources accessible through this catalog. In v1.1, APIs were documented only as Distributions inside a Dataset record. In v3.0, a DataService can be a first-class catalog resource. See DataService fields.
record Optional array of CatalogRecord objects Catalog records describing when and how individual datasets or services were registered in this catalog. Useful for tracking catalog provenance — when a dataset was added, by whom, and under what schema. Each CatalogRecord requires a modified date and a primaryTopic pointing to the described resource. Most agencies implementing v3.0 for the first time can omit this field and add it later as their catalog management matures.
themeTaxonomy Optional array of ConceptScheme objects A knowledge organization system used to classify the catalog's datasets. References the ConceptScheme class. Use this to declare the controlled vocabulary behind your theme values. Federal agencies may reference Data.gov topic categories, ISO 19115 topic categories for geospatial data, or their own agency-specific taxonomy.

Example

A minimal valid v3.0 catalog:

{
  "@id": "https://www.agency.gov/data.json",
  "@type": "dcat:Catalog",
  "conformsTo": {
    "@type": "Standard",
    "title": "DCAT-US 3.0",
    "identifier": "https://resources.data.gov/dcat-us/3.0.0"
  },
  "dataset": [
    {
      "@type": "Dataset",
      "title": "Agency Travel Data FY2024",
      "description": "Records of official travel expenditures during fiscal year 2024.",
      "identifier": "https://www.agency.gov/data/travel-fy2024",
      "publisher": {
        "@type": "Organization",
        "name": "Example Federal Agency"
      },
      "contactPoint": {
        "@type": "Kind",
        "fn": "Jane Smith",
        "hasEmail": "mailto:jane.smith@agency.gov"
      }
    }
  ]
}

A more complete catalog showing recommended fields and a DataService:

{
  "@id": "https://www.agency.gov/data.json",
  "@type": "dcat:Catalog",
  "conformsTo": {
    "@type": "Standard",
    "title": "DCAT-US 3.0",
    "identifier": "https://resources.data.gov/dcat-us/3.0.0"
  },
  "title": "Example Federal Agency Open Data Catalog",
  "description": "The comprehensive data inventory for Example Federal Agency, including all publicly available datasets and APIs.",
  "publisher": {
    "@type": "Agent",
    "name": "Example Federal Agency"
  },
  "contactPoint": [
    {
      "@type": "Kind",
      "fn": "Open Data Team",
      "hasEmail": "mailto:opendata@agency.gov"
    }
  ],
  "language": ["en"],
  "modified": "2025-04-15",
  "issued": "2014-11-06",
  "license": "https://creativecommons.org/publicdomain/zero/1.0/",
  "rights": ["This catalog is maintained by Example Federal Agency."],
  "spatial": [
    {
      "@type": "Location",
      "prefLabel": "United States"
    }
  ],
  "dataset": [
    {
      "@type": "Dataset",
      "title": "Agency Travel Data FY2024",
      "description": "Records of official travel expenditures during fiscal year 2024.",
      "identifier": "https://www.agency.gov/data/travel-fy2024",
      "publisher": {
        "@type": "Organization",
        "name": "Office of the Chief Financial Officer",
        "subOrganizationOf": [
          {
            "@type": "Organization",
            "name": "Example Federal Agency"
          }
        ]
      },
      "contactPoint": {
        "@type": "Kind",
        "fn": "Jane Smith",
        "hasEmail": "mailto:jane.smith@agency.gov"
      },
      "keyword": ["travel", "expenditure", "fiscal year"],
      "modified": "2024-10-15",
      "accessRights": "public",
      "bureauCode": ["015:11"],
      "programCode": ["015:001"]
    }
  ],
  "service": [
    {
      "@type": "DataService",
      "title": "Agency Open Data REST API",
      "description": "A REST API providing queryable access to agency datasets in JSON and CSV formats.",
      "endpointURL": ["https://api.agency.gov/v1/"],
      "endpointDescription": ["https://api.agency.gov/v1/openapi.json"],
      "publisher": {
        "@type": "Agent",
        "name": "Example Federal Agency"
      },
      "contactPoint": [
        {
          "@type": "Kind",
          "fn": "API Support Team",
          "hasEmail": "mailto:api-support@agency.gov"
        }
      ]
    }
  ]
}

Source: jsonschema/definitions/Catalog.json · Generated reference: jsonschema/docs/Catalog.md