Contextual entities

Last updated on 2025-04-17 | Edit this page

Overview

Questions

  • How can I describe things in the world?
  • How can I give details about licenses?

Objectives

  • Understand the difference between contextual and data entities
  • Add a contextual entity to the RO-Crate

Contextual entities

Entities that we have added under hasPart are considered data entities, while entities only referenced from those are considered contextual entities – they help explain the crate and its content.

You may notice the subtle difference between a data entity that is conceptually part of the RO-Crate and is file-like (containing bytes), while a contextual entity is a representation of a real-life organization that can’t be downloaded: following the URL, we would only get its description. The section contextual entities explores several of the entities that can be added to the RO-Crate to provide it with a context, for instance how to link to authors and their affiliations. Simplifying slightly, a data entity is referenced from hasPart in a Dataset, while a contextual entity is referenced using any other defined property.

Detailing licenses

We have previously declared two different license cross-references. While following the URLs in this case explain the licenses well, it is also best practice to include a very brief summary of contextual entities in the RO-Crate Metadata Document. This is more important if the cross-reference do not use a permalink and may change over time. As a minimum, each referenced entity should have a @type and name property. It is also possible to add url for more information.

Add licence entities

Add a contextual entity for each of the two licenses, see the licensing section for details:

JSON 

{
   "@id": "https://creativecommons.org/licenses/by-nc-sa/4.0/",
   "@type": "CreativeWork",
   "name": "CC BY-NC-SA 4.0 International",
   "description": "Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International"
},    
{
   "@id": "http://spdx.org/licenses/CC0-1.0",
   "@type": "CreativeWork",
   "name": "CC0-1.0",
   "description": "Creative Commons Zero v1.0 Universal",
   "url": "https://creativecommons.org/publicdomain/zero/1.0/"
},

An additional exercise is to try to unify the two entities so that both use spdx identifiers, remembering to update the corresponding license cross-references when changing the @id. However, not all licenses have a direct SPDX identifier.

Key Points

  • Contextual entities are not considered part of the crate
  • Cross-references should be expanded as contextual entities
  • It is recommended to provide a human-readable name for licenses