Linked Art API: Digital Object

Introduction

The Digital Object API is a method of getting access to descriptions of digital content, such as images, documents or other electronic media, regardless of whether that file is accessible over the network at all. Access to the digital content itself, when it is available online, is provided through the access_point property within the description. The Digital Object API is of average complexity with many familiar properties and patterns, plus several additions to describe the object's relationship to other entities.

For more information about the usage of Digital Object records, please see the Digital model description.

Property Definitions

Dereferencing an entity via the Digital Object endpoint would result in a JSON-LD document containing a single JSON object with the following properties.

Properties of Digital Objects

Property Name Datatype Requirement Description
@context string, array Required The value MUST be the URI of the Linked Art context as a string, "https://linked.art/ns/v1/linked-art.json" or an array in which the URI is the last entry to allow for extensions
id string Required The value MUST be the HTTP(S) URI at which the digital object's description can be dereferenced
type string Required The class for the digital object, which MUST be the value "DigitalObject"
_label string Recommended A human readable label for the digital object, intended for developers
classified_as array Recommended An array of json objects, each of which is a classification of the digital object and MUST follow the requirements for Type
identified_by array Recommended An array of json objects, each of which is a name/title of the digital and MUST follow the requirements for Name, or an identifier for the digital object and MUST follow the requirements for Identifier
referred_to_by array Optional An array of json objects, each of which is a human readable statement about the digital object and MUST follow the requirements for Statement
equivalent array Optional An array of json objects, each of which is a reference to an external identity of the current digital object
member_of array Optional An array of json objects, each of which is a Set that the current digital object is a member of and MUST follow the requirements for a reference to a Set
attributed_by array Optional An array of json objects, each of which is a Relationship Assignment that relates the current digital object to another entity
dimension array Optional An array of json objects, each of which is a Dimension, such as height, width or total number of bytes, of the described digital object
part_of array Optional An array of json objects, each of which is a reference to another Digital Object that the current digital object is a part of.
format string Optional The media type of the described digital object, for example "image/jpeg"
conforms_to array Optional An array of json objects, each of which is a reference to an external specification that the current digital object conforms to. The type value of the reference MUST be "InformationObject"
digitally_carries array Optional An array of json objects, each of which is a reference to a Textual Work that is carried by this digital object
digitally_shows array Optional An array of json objects, each of which is a reference to a Visual Work that is shown by this digital object
digitally_available_via array Optional An array of json objects, each of which is a Digital Service structure, defined below
access_point array Optional An array of json objects, each of which is a reference to a URI from which a representation of the digital object can be retrieved
created_by json object Optional A json object representing the creation of the text, which follows the requirements for Creations described below, for when the digital object was first created
used_for array Optional An array of json objects, each of which is a Publication Activity, which follows the requirements for Publications described below, for when the digital object was made available

Properties of Creations, Publication Activities

Property Name Datatype Requirement Description
id string Optional If present, the value MUST be a URI identifying the creation or publication
type string Required The class for the creation, which MUST be the value "Creation" or "Activity"
_label string Recommended A human readable label for the creation or publication, intended for developers
identified_by array Recommended An array of json objects, each of which is a name for the creation or publication and MUST follow the requirements for Name, or an identifier for the creation or publication and MUST follow the requirements for Identifier
classified_as array Recommended An array of json objects, each of which is a further classification of the creation or publication and MUST follow the requirements for Type
timespan json object Recommended A json object recording when the creation or publication occured, which MUST follow the requirements for timespans
referred_to_by array Optional An array of json objects, each of which is an embedded statement about the creation or publication
took_place_at array Optional An array of json objects, each of which is a reference to a Place where the creation or publication occured
caused_by array Optional An array of json objects, each of which is a reference to an Event that caused the creation or publication to occur
influenced_by array Optional An array of json objects, each of which is a reference to an entity that influenced the creation or publication in some noticable fashion
carried_out_by array Optional An array of json objects, each of which is a reference to a Person or Group that carried out the creation or publication
used_specific_object array Optional An array of json objects, each of which is a reference to an entity that was used in the creation or publication
technique array Optional An array of json objects, each of which is a technique used in this event and MUST follow the requirements for Type
part array Optional An array of json objects, each of which is another instance of this same type for describing different aspects of the creation or publication

Properties of Digital Services

Property Name Datatype Requirement Description
@context string, array Required The value MUST be the URI of the Linked Art context as a string, "https://linked.art/ns/v1/linked-art.json" or an array in which the URI is the last entry to allow for extensions
id string Required The value MUST be the HTTP(S) URI at which the digital object's description can be dereferenced
type string Required The class for the digital object, which MUST be the value "DigitalService"
_label string Recommended A human readable label for the digital object, intended for developers
classified_as array Recommended An array of json objects, each of which is a classification of the digital object and MUST follow the requirements for Type
identified_by array Recommended An array of json objects, each of which is a name/title of the digital and MUST follow the requirements for Name, or an identifier for the digital object and MUST follow the requirements for Identifier
referred_to_by array Optional An array of json objects, each of which is a human readable statement about the digital object and MUST follow the requirements for Statement
access_point array Optional An array of json objects, each of which is a reference to a URI at which the service can be interacted with
conforms_to array Optional An array of json objects, each of which is a reference to an external specification that the digital service conforms to. The type value of the reference MUST be "InformationObject"

Property Diagram

diagram

JSON Schema

See the schema documentation and the schema itself

Incoming Properties

Digital Object instances are typically found as the object of the following properties, other than the self-referential properties above. This list is not exhaustive, but is intended to cover the likely cases where other endpoints refer to digital objects.

Property Name Source Endpoint Description
digitally_carried_by Textual Work Texts can be carried by physical objects, or digitally carried by digital objects
digitally_shown_by Visual Work Similarly, Image content can be digitally shown by digital objects

Example

The JSON for a Digital Object entry for a digital image of a self-portrait by Van Gogh could be as below.

{
  "@context": "https://linked.art/ns/v1/linked-art.json",
  "id": "https://linked.art/example/digital/0",
  "type": "DigitalObject",
  "_label": "Digital Image of Self-Portrait of Van Gogh",
  "classified_as": [
    {
      "id": "http://vocab.getty.edu/aat/300215302",
      "type": "Type",
      "_label": "Digital Image"
    }
  ],
  "identified_by": [
    {
      "type": "Name",
      "content": "Self-Portrait Dedicated to Paul Gauguin"
    },
    {
      "type": "Identifier",
      "classified_as": [
        {
          "id": "http://vocab.getty.edu/aat/300404621",
          "type": "Type",
          "_label": "Owner-Assigned Number"
        }
      ],
      "content": "47174896"
    }
  ],
  "dimension": [
    {
      "type": "Dimension",
      "classified_as": [
        {
          "id": "http://vocab.getty.edu/aat/300055644",
          "type": "Type",
          "_label": "Height"
        }
      ],
      "value": 2550,
      "unit": {
        "id": "http://vocab.getty.edu/aat/300266190",
        "type": "MeasurementUnit",
        "_label": "pixels"
      }
    },
    {
      "type": "Dimension",
      "classified_as": [
        {
          "id": "http://vocab.getty.edu/aat/300055647",
          "type": "Type",
          "_label": "Width"
        }
      ],
      "value": 2087,
      "unit": {
        "id": "http://vocab.getty.edu/aat/300266190",
        "type": "MeasurementUnit",
        "_label": "pixels"
      }
    }
  ],
  "member_of": [
    {
      "id": "https://linked.art/example/set/0",
      "type": "Set",
      "_label": "Images of Self-Portraits of Van Gogh"
    }
  ],
  "access_point": [
    {
      "id": "https://ids.lib.harvard.edu/ids/iiif/47174896/full/full/0/default.jpg",
      "type": "DigitalObject"
    }
  ],
  "digitally_shows": [
    {
      "type": "VisualItem",
      "_label": "Visual Content of Self-Portrait of Van Gogh"
    }
  ],
  "format": "image/jpeg",
  "digitally_available_via": [
    {
      "type": "DigitalService",
      "_label": "IIIF Service",
      "access_point": [
        {
          "id": "https://ids.lib.harvard.edu/ids/iiif/47174896",
          "type": "DigitalObject"
        }
      ],
      "conforms_to": [
        {
          "id": "https://iiif.io/api/image/2/context.json",
          "type": "InformationObject"
        }
      ]
    }
  ],
  "created_by": {
    "type": "Creation",
    "carried_out_by": [
      {
        "id": "https://linked.art/example/group/harvardartmuseums.org",
        "type": "Group",
        "_label": "Harvard Art Museums"
      }
    ],
    "used_specific_object": [
      {
        "id": "https://harvardartmuseums.org/collections/object/299843",
        "type": "HumanMadeObject",
        "_label": "Self-Portrait of Van Gogh"
      }
    ]
  },
  "part_of": [
    {
      "id": "https://iiif.harvardartmuseums.org/manifests/object/299843",
      "type": "DigitalObject",
      "_label": "IIIF Manifest"
    }
  ]
}

graph TD classDef object stroke:black,fill:#E1BA9C,rx:20px,ry:20px; classDef actor stroke:black,fill:#FFBDCA,rx:20px,ry:20px; classDef type stroke:red,fill:#FAB565,rx:20px,ry:20px; classDef name stroke:orange,fill:#FEF3BA,rx:20px,ry:20px; classDef dims stroke:black,fill:#c6c6c6,rx:20px,ry:20px; classDef infoobj stroke:#907010,fill:#fffa40,rx:20px,ry:20px classDef timespan stroke:blue,fill:#ddfffe,rx:20px,ry:20px classDef place stroke:#3a7a3a,fill:#aff090,rx:20px,ry:20px classDef event stroke:#1010FF,fill:#96e0f6,rx:20px,ry:20px classDef literal stroke:black,fill:#f0f0e0; classDef classstyle stroke:black,fill:white; O1(digital0) class O1 digital; O1-- type -->O1_0[DigitalObject] class O1_0 classstyle; O1-- _label -->O1_4("''Digital Image of Self-Portrait of Van Gogh''") class O1_4 literal; O2(aat:300215302) class O2 type; O2-- type -->O2_0[Type] class O2_0 classstyle; O2-- _label -->O2_3("''Digital Image''") class O2_3 literal; O1-- classified_as -->O2 O3( _ ) class O3 name; O3-- type -->O3_0[Name] class O3_0 classstyle; O3-- content -->O3_2("''Self-Portrait Dedicated to Paul Gauguin''") class O3_2 literal; O1-- identified_by -->O3 O4( _ ) class O4 name; O4-- type -->O4_0[Identifier] class O4_0 classstyle; O5(aat:300404621) class O5 type; O5-- type -->O5_0[Type] class O5_0 classstyle; O5-- _label -->O5_3("''Owner-Assigned Number''") class O5_3 literal; O4-- classified_as -->O5 O4-- content -->O4_3("''47174896''") class O4_3 literal; O1-- identified_by -->O4 O6( _ ) class O6 dims; O6-- type -->O6_0[Dimension] class O6_0 classstyle; O7(aat:300055644) class O7 type; O7-- type -->O7_0[Type] class O7_0 classstyle; O7-- _label -->O7_3("''Height''") class O7_3 literal; O6-- classified_as -->O7 O6-- value -->O6_3(2550) class O6_3 literal; O8(aat:300266190) class O8 type; O8-- type -->O8_0[MeasurementUnit] class O8_0 classstyle; O8-- _label -->O8_3("''pixels''") class O8_3 literal; O6-- unit -->O8 O1-- dimension -->O6 O9( _ ) class O9 dims; O9-- type -->O9_0[Dimension] class O9_0 classstyle; O10(aat:300055647) class O10 type; O10-- type -->O10_0[Type] class O10_0 classstyle; O10-- _label -->O10_3("''Width''") class O10_3 literal; O9-- classified_as -->O10 O9-- value -->O9_3(2087) class O9_3 literal; O9-- unit -->O8 O1-- dimension -->O9 O11(https://iiif.harvardartmuseums.org/manifests/object/299843) class O11 digital; O11-- type -->O11_0[DigitalObject] class O11_0 classstyle; O11-- _label -->O11_3("''IIIF Manifest''") class O11_3 literal; O1-- part_of -->O11 O12(set0) class O12 infoobj; O12-- type -->O12_0[Set] class O12_0 classstyle; O12-- _label -->O12_3("''Images of Self-Portraits of Van Gogh''") class O12_3 literal; O1-- member_of -->O12 O13(https://ids.lib.harvard.edu/ids/iiif/47174896/full/full/0/default.jpg) class O13 digital; O13-- type -->O13_0[DigitalObject] class O13_0 classstyle; O1-- access_point -->O13 O14( _ ) class O14 infoobj; O14-- type -->O14_0[VisualItem] class O14_0 classstyle; O14-- _label -->O14_2("''Visual Content of Self-Portrait of Van Gogh''") class O14_2 literal; O1-- digitally_shows -->O14 O1-- format -->O1_12("''image/jpeg''") class O1_12 literal; O15( _ ) class O15 digital; O15-- type -->O15_0[DigitalService] class O15_0 classstyle; O15-- _label -->O15_2("''IIIF Service''") class O15_2 literal; O16(https://ids.lib.harvard.edu/ids/iiif/47174896) class O16 digital; O16-- type -->O16_0[DigitalObject] class O16_0 classstyle; O15-- access_point -->O16 O17(https://iiif.io/api/image/2/context.json) class O17 infoobj; O17-- type -->O17_0[InformationObject] class O17_0 classstyle; O15-- conforms_to -->O17 O1-- digitally_available_via -->O15 O18( _ ) class O18 event; O18-- type -->O18_0[Creation] class O18_0 classstyle; O19(groupharvardartmuseums.org) class O19 actor; O19-- type -->O19_0[Group] class O19_0 classstyle; O19-- _label -->O19_3("''Harvard Art Museums''") class O19_3 literal; O18-- carried_out_by -->O19 O20(https://harvardartmuseums.org/collections/object/299843) class O20 object; O20-- type -->O20_0[HumanMadeObject] class O20_0 classstyle; O20-- _label -->O20_3("''Self-Portrait of Van Gogh''") class O20_3 literal; O18-- used_specific_object -->O20 O1-- created_by -->O18
Other Representations: JSON-LD (raw) | JSON-LD (playground) | Turtle (raw) | Turtle (styled)