Skip to end of banner
Go to start of banner

Annotation API Documentation

Skip to end of metadata
Go to start of metadata

You are viewing an old version of this page. View the current version.

Compare with Current View Page History

« Previous Version 10 Next »

The Annotation API is allows users to search, obtain and contribute annotations about items in Europeana. Annotations are user-contributed or software-generated enhancements, additions or corrections to (or a selection of) metadata or content resources. We adopted the Web Annotation Data Model as a base model for the representation of annotations and as a format for exchanging annotations between client applications and the API, but also the Web Annotation Protocol as base protocol for the API.

The Annotation Data Model

What are annotations?

Annotations (in the Europeana context) are user-contributed or software-generated enhancements to (a selection of) metadata or content resource. The Annotations API adopted the Web Annotation Data Model (WADM) as a base model for representing and exchanging annotations between client applications and the API. The WADM is a W3C recommendation that describes a model and format to share annotations across different platforms.

Please note that, even though we have adopted WADM as underlying data model for this API, it is not expected that we support the full extent of the model. We thus advise to look at the EDM Annotations Profile which describes the basics of our implementation and, in particular, the section on Annotation Scenarios for a comprehensive list of the different kinds of annotations that we support.

Basics of the model

In WADM, an annotation is essentially a reified relation between two or more resources, typically a body and a target, and conveys that the body reflects what is intended to be said about the target. A body can also be absent to describe situations where a target is simply bookmarked. A target can represent a resource or just a part of it that is being annotated.

Being reified as a class enables an annotation to be further described with a motivation which expresses the reason why the annotation was created but also some provenance information such as the user that created the annotation and the software application that was used, as well as the times when it was initially created and sent to the API.

 The following fields are used to describe an Annotation resource in JSON-LD

Field

Datatype

Description

Annotation

@context

String (URL)

The URL of the JSON-LD context. (always with value "http://www.w3.org/ns/anno.jsonld")

id

String (URI)

The identifier of the Annotation. It is automatically generated upon creation.

type

String

The type of the resource. Always set to "Annotation".

created

String (DateTime)

The time at which the Annotation was created by the client application. It is expressed in ISO8601 format with a timezone specified.

creator

Object (Agent)

The agent responsible for creating the Annotation. This may be either a human or software agent and is always determined by the user information present in the JWT token used upon creation.

generated

String (DateTime)

The time at which the annotation was sent to the server. It is expressed in ISO8601 format with a timezone specified.

generator

Object (Software)

The agent responsible for generating the Annotation. The client application used to submit the annotation to the server and is always determined by the client information present in the JWT token used upon creation.

motivation

String

Expresses the reason why the annotation was created. Depending on the application scenario, the value can one of the following: "tagging", "linking", "describing", “highlighting“, “transcribing“, “translating“, “captioning“, “subtitling“, “linkForContributing“

body

String or Object (Semantic Resource or Textual Body)

A body conveying what is intended to be said about the target. If the value is provided as a string, then it is interpreted as the URI and must only be used for the semantic tagging scenario. See the application scenarios section for more information.

bodyValue

String

A string conveying the tag text. This field must only be used in combination with "tagging" as motivation and when the language of the tag is not known. Otherwise, it is recommended to use the body field as defined in the Application Scenarios section.

target

String, Array (String), Media Resource or Array (Media Resource)

The URL of the resource that is being annotated, or a specific resource in the case of media annotations. An array of URLs may also be set (mostly used for the object linking).

User Agent

An Agent can be either a Person or a Software. Typically the Person corresponds to the user that created the annotation while the Software reflects the client application that was used to create it. A Software can also create annotations if they result from an automatic process.

id

String

The identifier of the Agent. This identififer is obained from the JWT token used upon creation.

type

String

The type of the resource. Either "Person" or "Software".

Software Agent

An Agent can be either a Person or a Software. Typically the Person corresponds to the user that created the annotation while the Software reflects the client application that was used to create it. A Software can also create annotations if they result from an automatic process.

id

String

The identifier of the Agent. This identififer is obained from the JWT token used upon creation.

type

String

The type of the resource. Either "Person" or "Software".

Semantic Resource

A Semantic Resource is used whenever an external resource needs to be referenced as the body of the annotation. It is mostly used for Semantic Tagging.

type

String

Always "SpecificResource".

source

String (URI)

The URI of the resource being referred as body.

language

String (ISO639)

The ISO639 language code corresponding to the language of the resource.

Media Resource

Annotations that refer to a media resource require that an oa:SpecificResource object is defined so that the context in which the annotation was made is captured by the annotation. Besides context, a Specific Resource can be used to capture any additional information about how a target is used in the Annotation. The following table lists the properties supported by this class.

type

String

Always "SpecificResource".

source

String (URL)

The URL that identifies the media resource which is the ultimate target of the annotation.

scope

String (URI)

The unique identifier of the Europeana item to which this media resource is associated. In more general terms, scope is used to define the context in which the annotation was made, in terms of the resources that the annotator was viewing or using at the time.

 Example of the annotation model

SHOW A DYNAMIC EXAMPLE

Annotation Scenarios

The Annotations API supports different types of annotations. This page explains the types of annotations that are currently supported, providing examples on how to represent them in the API.

The examples used in this Section are shortened versions of the Annotation Model, you can find an example of a complete Annotation Data Model implementation here.

Simple tags (without language)

A simple tag is a short textual description of a resource. This scenario only applies when the language of the tag is not known, otherwise see the scenario described in the next Section.

Examples:

church
blue
black and white

Requirement:

A maximum of 64 characters is allowed for a simple tag. A tag cannot be a URL.

In the API:

Set the "motivation" to "tagging" and set the tag within the "bodyValue" field.

Availability:

Since version 0.2.1.

 Example: tagging a Europeana item with the word "painting".
{
  "motivation": "tagging",
  "bodyValue": "painting",
  "target": "http://data.europeana.eu/item/92062/BibliographicResource_1000126189360"
}

Simple tags (with language)

A simple tag is a short textual description of a resource.

Examples:

church
blue
black and white

Requirement:

A maximum of 64 characters is allowed for a simple tag. A tag cannot be a URL and the language information must be specified.

In the API:

Set the "motivation" to "tagging" and set the tag within the "body" field as a Textual Body.

Availability:

Since version 0.2.1.

 Example: tagging a Europeana item with the English word "painting"
{
  "motivation": "tagging",
  "body": {
    "type": "TextualBody",
    "value": "painting",
    "language": "en"
 },
  "target": "http://data.europeana.eu/item/92062/BibliographicResource_1000126189360"
}

Semantic tags

A semantic tag is a tag to a resource from a controlled vocabulary, making it machine-interpretable.

Example:

This object in Europeana is somehow related to France (http://sws.geonames.org/2988507).

Requirement:

Any URI is accepted as semantic resource. In the future, it will be limited to a controlled list of acceptable domains.

In the API:

Set the "motivation" to "tagging" and set as body the URI for the semantic resource taken from a contolled vocabulary.

Availability:

Since version 0.2.1.

 Example: tagging a Europeana item with the semantic resource for Paris from Geonames.
{
  "motivation": "tagging",
  "body": "http://sws.geonames.org/2988507",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

An object link is a relationship between two (Europeana) objects. This relationship can be any.

Example:

This object in Europeana is (in some way) similar to this object.

Requirement:

An object link can only be made between two Europeana objects.

In the API:

Set the "motivation" to "linking" and set as target an array containing the URIs of both objects.

Availability:

Since version 0.2.1.

 Example: linking two Europeana items together.
{
  "motivation": "linking",
  "target": [
      "http://data.europeana.eu/item/92062/BibliographicResource_1000126189360",
      "http://data.europeana.eu/item/92062/BibliographicResource_1000126189361"
  ]
}

Geo Tags

A geo-tag adds a geographical location to an item.

Example:

This object in Europeana was located at latitude 52.081131 and longitude 4.324053. .

In the API:

Set the "motivation" to "tagging" and include the "type", "lat" and "long" attributes in the body as per the example below.

Availability:

Since version 0.2.2.

 Example: tagging a Europeana item with a geographical location.
{
  "motivation": "tagging",
  "body": {
    "@context": "http://www.europeana.eu/schemas/context/entity.jsonld",
    "type": "Place",
    "lat": "52.081131",
    "long": "4.324053"
  },
  "target": "http://data.europeana.eu/item/92034/GVNRC_NFA03_kop_6_3"
}

Annotating media resources

Annotating a media resource means that the target of the annotation is not the Europeana item but instead a specific media resource within that item.

In the API:

Set the "target" of the annotation to a JSON object with the "scope" holding the unique identifier of the Europeana item and the "source" field the URL of the actual media resource being annotated.

Availability:

Since version 0.2.8.

 Example: tagging a sound track of an Europeana item with the simple tag "Folk Music".
{
  "motivation": "tagging",
  "bodyValue": "Folk Music",
  "target": {
    "type": "SpecificResource",
    "scope": "http://data.europeana.eu/item/2059207/data_sounds_T471_5",
    "source": "http://comhaltasarchive.ie/tracks/12535"
  }
}

Transcriptions

A transcription is typically an annotation expressing a relation between an image and the text that is represented on that image. Besides the text, the annotation can also refer to a page where the text is displayed, like in the example below.

In the API:

Set the "motivation" to "transcribing" and apply the same criteria as for media resources.

Availability:

Since version 0.2.8.

 Example: annotating the image of an Europeana item with the transcription page available at Transcribathon.

Example: annotating the image of an Europeana item with the transcription page available at Transcribathon.

{
  "motivation": "transcribing",
  "body": {
    "id": "https://europeana.transcribathon.eu/documents/story/item/?item=39378387",
    "language": "de",
    "format": "text/html"
  },
  "target": {
    "scope": "http://data.europeana.eu/item/743/_nhp5sXg",
    "source": 
    "https://glam.uni.wroc.pl/iiif/image-api/RKP_HAASE_371_62468_0001/full/full/0/default.jpg"
  }
}

Getting Started

Access keys

While this API is in an Alpha state you will need to use a separate API key (other than for the main Europeana REST API) to start using it. You can use the following keys:

Environment

Details

Test

API key apidemo with user token tester1 (allows to create, update & remove annotations on behalf of a test user in the Annotations API test environment).

Production

API key apidemo (allows to search and retrieve annotations in the Annotations API production (live) environment).

Creating annotations in the production (live) environment is currently limited to only selected partners, this will be opened up as part of the Beta release.

Request

Every Annotations API call is an HTTP request in a specified format that is sent to the Annotations API service. The API root URLs for the two environments are located at:

https://test-annotations.europeana.eu/annotation (test)
https://www.europeana.eu/api/annotations (production)

Response

This API only supports the JSON-LD format, which is the Linked Open Data version of JSON (with the same syntax as JSON). The request and response format does not need to be passed along to the API, if not provided it will fallback to the default. You can provide the format either via the URL (extension) or via the "Accept" header. To specify the request and response format you can either do:

/search.jsonld?wskey=xxxxx&query=*:*

Or:

Request header: "Accept: application/ld+json"
/search?wskey=xxxxx&query=*:*

Retrieving annotations

Retrieve annotations by their identifier.

GET /{provider}/{identifier}

Response

 Example Response from the Read method in the Annotation API
HTTP/1.1 200 OK
Content-Type: application/ld+json
{
  "@context": "http://www.w3.org/ns/anno.jsonld",
  "id": "http://data.europeana.eu/annotation/base/1",
  "type": "Annotation",
  "created": "2016-01-31T12:03:45Z",
  "generated": "2016-01-31T12:04:00Z",
  "generator": "http://www.europeana.eu",
  "bodyValue": "Trombone",
  "motivation": "tagging",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

See data model for more information on the representation of an annotation.

Discovery

Search for annotations.

GET /search

Request

 Table of parameters that can be sent in an Annotation Search Request

Parameter

Datatype

Description

query

String

The search term(s), this is mandatory.

profile

String

The search profile which determines the extent of information returned as search result. Currently, two options are supported: "minimal" which returns only the identifier of the annotation; and "standard" (the default) which returns the annotation as it was sent to the API.

qf

String

Query filter, to search on specific fields. The list of fields is presented below.

facet

String

Includes a field to be used as facet in the response (see below which fields can be used as facets). More than one field can be added if separated by a space.

pageSize

Number

The number of records to return per page. For minimal profile, the maximum is 10.000 while for the standard profile is 100, with 10 as default for both profiles.

page

Number

The page of the search results, defaults to 0 (first page).

sort

String

Includes a field to be used for sorting. One of: created, generated or modified.

sortOrder

String

Order of sorting, either "asc" (ascending) or "desc" (descending).

Search and Facet fields

The following table shows the fields that can be used for searching annotations and the ones that can be used for faceting:

 Table of search and facet fields for the Search method of the Annotations API

Field

Datatype

Used for Facetting

Description

motivation

keyword

yes

motivation of the Annotation

anno_uri

keyword

complete identifier of an Annotation

anno_id

keyword

local identifier of an Annotation (/<provider>/<identifier>)

generator_uri

keyword

yes

complete identifier of the generator

generator_name

keyword

yes

name of the generator

generated

date

date on which the Annotation was first provided to the API

creator_uri

keyword

yes

complete identifier of the creator

creator_name

keyword

yes

name of the user that created the annotation

created

date

date on which the Annotation was created by the annotation client application

modified

date

date on which the Annotation was last modified

moderation_score

integer

yes

sum of all reports made to an Annotation by other users

text

text

searches in all searchable text in an Annotation

body_value

text

yes

value within the body of an Annotation, applies to e.g. simple tagging

body_uri

keyword

yes

complete identifier of the resource within the body of an Annotation, applies to e.g. semantic tagging

target_uri

keyword

yes

complete identified of the target(s) of an Annotation

target_record_id

keyword

yes

local identifier of a record when the target is a record (/collectionId/objectId)

link_resource_uri

keyword

yes

complete identifier of the resource being linked to (ie. through the relation property)

link_relation

keyword

yes

property being used to link two resources.

Response

 An example of a Response to a Search Request from the Annotations API
{
  "@context": "http://www.w3.org/ns/anno.jsonld",
  "id": "http://annotations.europeana.eu/annotation/search?wskey=xxxxx&query=*:*&page=0&pageSize=10",
  "items": [
    "http://data.europeana.eu/annotation/base/1",
    "http://data.europeana.eu/annotation/base/2",
    [..]
  ],
  "next": "http://annotations.europeana.eu/annotation/search?wskey=xxxxx&query=*:*&page=1&pageSize=10",
  "partOf": {
     "id": "http://annotations.europeana.eu/annotation/search?wskey=xxxxx&query=*:*",
     "total": 135610
  },
  "total": 10,
  "type": "AnnotationPage"
}
 Example: Search for recently added tags:

/search?wskey=xxxxx&profile=minimal&query=*:*&qf=motivation:tagging&sort=created&sortOrder=desc

 Example: Search for tags for Europeana record ID /92028/532E53363138382D2F290A40B3CA26B3889A6907:

/search?wskey=xxxxx&profile=minimal&query=target_id:"/92028/532E53363138382D2F290A40B3CA26B3889A6907"

 Example: Don't show annotations which are reported by two or more different users:

/search?wskey=xxxxx&profile=minimal&query=*:*&qf=moderation_score:[-1 TO *]

Note that providing *:* as a search query means you will get all annotations.

Provision

Using the PUT/POST/DELETE methods for this API is currently not publicly available.. You can request access to the write methods by emailing us with your use case.

Create

The API has a generic method available for the creation of annotations. The creation method expects a body payload in the request with the full annotation. Alternatively you can provide this information as part of the body parameter.

POST http://annotations.europeana.eu/annotation/

Request

 Example Request for the Create method in the Annotation API

An example to create a simple tag:

POST  http://annotations.europeana.eu/annotation/?wskey=YOUR_KEY&userToken=YOUR_TOKEN HTTP/1.1
Accept: application/ld+json
Content-Type: application/ld+json
Content-Length: 999
{
  "motivation": "tagging",
  "bodyValue": "Trombone",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

Note that the motivation for a simple and a semantic tag is always "tagging", whereas the motivation for object linking scenarios is "linking".

Response

 Example Response to a Create request in the Annotation API

Response to the example request:

Content-Type: application/ld+json
ETag: "_87e52ce126126"
Link: <http://www.w3.org/ns/ldp#Resource>l; rel="type"
Allow: POST,GET,OPTIONS,HEAD
Vary: Accept
Content-Length: 999
{
  "@context": "http://www.w3.org/ns/anno.jsonld",
  "id": "http://data.europeana.eu/annotation/base/1",
  "type": "Annotation",
  "created": "2016-01-31T12:03:45Z",
  "creator": "http://data.europeana.eu/user/55376",
  "generated": "2016-01-31T12:04:00Z",
  "generator": "http://data.europeana.eu/provider/historypin",
  "bodyValue": "Trombone",
  "motivation": "tagging",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

For more examples and information on the data model for an annotation, see data model.

Update

Update the contents of an annotation. For this you can send a PUT request to the ID of the annotation. You can only update the annotations you have created yourself.

PUT /base/1

Request

You can provide the same content in the Update method as you’d provide for the Create method. Note that you have to provide the full annotation body, you currently cannot update parts of the annotation.

 Example Request of the Update Method in the Annotation API
PUT /base/1 HTTP/1.1
Accept: application/ld+json
{
  "bodyValue": "Trombone",
  "motivation": "tagging",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

Response

 Example Response of the Update Method in the Annotation API
HTTP/1.1 200 OK
Content-Type: application/ld+json
{
  "@context": "http://www.w3.org/ns/anno.jsonld",
  "id": "http://data.europeana.eu/annotation/base/1",
  "type": "Annotation",
  "created": "2016-01-31T12:03:45Z",
  "generated": "2016-01-31T12:04:00Z",
  "generator": "http://www.europeana.eu",
  "bodyValue": "Trombone",
  "motivation": "tagging",
  "target": "http://data.europeana.eu/item/09102/_UEDIN_214"
}

Delete

Delete an annotation. You can send a DELETE HTTP request using the ID of the annotation. You can only delete the annotations you have created yourself. Deletion means the annotation will not be available anymore for search, and only available for retrieval based on the ID of the annotation.

DELETE /base/1

Request

DELETE /collections/1 HTTP/1.1

Response

HTTP/1.1 204 NO CONTENT
Content-Length: 0

Console

Roadmap and Changelog

The current version of the Annotations API is 0.3.3 (August 2022). It is currently available as a Public Alpha, which is the first public version released primarily to get feedback from you. Do note that this means that changes can be introduced which could break backwards compatibility. It also means that to use this API you need a separate API key than for the other Europeana APIs. To see the changes made for the current version and also all previous releases, see the API changelog in the project GitHub.

Credits

This API was initially developed as part of the Europeana Sounds project. It's development has been carried out by the AIT Austrian Institute of Technology in cooperation with the Europeana Foundation.

  • No labels