V 1.0 of the GDL metadata

The GDL project has defined a commons set of metadata based on the Learning Resources Metadata Initiative(LRMI). This will ensure quality and allow for the GDL platform to present resources with a consistent set of metadata.

The Global Digital Library metadata is based on the LRMI Specification Version 1.1. The LRMI project has been inspired by other projects with similar visions in furtherance of its goal of interoperating with other specifications. These initiatives are:

Mandatory properties marked with *

Property Expected Type Description
metapicture GIF, JPEG, PNG or SVG Picture for metadescription
Name * schema.org/Text The title of the resource.
Link * URL Link til to the resources
linkEpub * URL Link til EPUB(if different than link)
about * schema.org/Thing The subject of the content.
dateCreated * schema.org/Date The date on which the resource was created.
author * schema.org/Person The individual credited with the creation of the resource.
subject  The subject of the book, according to one of the following schemas:

BIC (UK and Australia)
BISAC [2015 Edition] (North America)
WGSneu (Germany)
C-Code (Japan)
CLIL (France)
UDC (Russia)
GKSS (South Korea)
Manga (Japan and South Korea)

numberOfPages Referring to numbers of pages in a book(if it is a book)
translator schema.org/Person The individual credited with the translation of the resource.
Publisher * schema.org/Organization The organization credited with publishing the resource.
inLanguage * schema.org/Language or Language code (ISO-639-2) 3-letter The primary language of the resource.
License * Url or CreativeWork A license document that applies to this content, typically indicated by URL.
isBasedOnUrl schema.org/URL A resource that was used in the creation of this resource. This term can be repeated for multiple sources.
educationalAlignment schema.org/AlignmentObject An alignment to an established educational framework.
educationalUse schema.org/Text The purpose of the work in the context of education.

Ex: “assignment”
Ex: “group work”

timeRequired schema.org/Duration (ISO


Approximate or typical time it takes to work with or through this learning resource for the typical intended target audience.

Ex: “PT30M”
Ex: “PT1H25M”

typicalAgeRange schema.org/Text The typical range of ages the content’s intended end user.

Ex: “7-9”
Ex: “18-“

level Indicates reading level.
interactivityType schema.org/Text The predominant mode of learning supported by the learning resource. Acceptable values are active, expositive, or mixed.

Ex: “active”
Ex: “mixed”

learningResourceType schema.org/Text The predominant type or kind characterizing the learning resource.

Ex: “presentation”
Ex: “handout”

accessibilityAPI Text Indicates that the resource is compatible with the referenced accessibility API. (WebSchemas wiki lists possible values).
accessibilityControl Text Identifies input methods that are sufficient to fully control the described resource. (WebSchemas wiki lists possible values).
accessibilityFeature Text Content features of the resource, such as accessible media, alternatives and supported enhancements for accessibility. (WebSchemas wiki lists possible values).
accessibilityHazard Text A characteristic of the described resource that is physiologically dangerous to some users. Related to WCAG 2.0 guideline 2.3. (WebSchemas wiki lists possible values).

File formats

Document and file formats for different types of e-books and content (storybooks, textbooks, etc) and other resources that are committed to the GDL platform, there are two preferred formats:

In addition, we ask for a print ready version in PDF(PDF 1.4 – 1.7).

All text needs to be encoded in UTF-8. This includes both metadata and textual content.

Creative Commons toolkit

The GDL core platform will hold digital copies of Creative Commons or otherwise openly licensed, publicly accessible materials. We encourage all projects developing content to visit creativecommons.org for more information.

The primary licenses for the GDL will be CC BY and CC BY-SA, these licenses drive innovation and creativity – including commercial reuse. They also support the overall goal of sharing, translation, and contextualization of early grade reading educational materials, open textbooks and open educational resources. The GDL project will also accept other CC licenses.

For some projects, it will be useful to use the cc toolkit for user-generated content platforms that want to address the increasing public demand for sharing under CC licenses and public domain tools.


The GDL project will follow the principles of universal design and accessibility and will have a strong focus on making all content generally accessible, including for those with print disabilities, i.e. blindness or low vision, severe dyslexia, or mobility impairment.

The complete set of requirements will be defined consultation with a wide range of stakeholders in the months to come. Pending this process we encourage all content developing projects to read more about general EPUB accessibility guidelines.

The Web Content Accessibility Guidelines (WCAG) 2.0 covers a wide range of recommendations for making web content more accessible. GDL will follow these guidelines to secure that the content is accessible for all users. By following these guidelines one will also often make the web content more usable in general.