This document outlines some of the metadata ccLearn is utilizing for the Universal Education Search project. This information applies to RSS and Atom feeds which we use to direct the crawl, as well as to embedded metadata (RDFa) that might be included in pages.
Presently, ccLearn is exposing the following data:
- Title (DC:title): A brief descriptive title for the resource.
- Summary: A relatively short summary (description) of the resource.
- License: The URL of the work's license; e.g., http://creativecommons.org/licenses/by/3.0/.
- Education level (DCT:educationLevel): What grade(s) or age-level(s) this material is suitable for.
- Language (
xml:lang, DCT:language): The language(s) of the referenced resource (not of your site).
- Subject (
DCT:subject): The subject(s) of the resource; e.g., math.
The CC Specific fields do not have native Atom or RSS element definitions. For these fields we suggest that they be embedded as category or tag specifications (
<category> in Atom) with a specific prefix. These have the general format of:
For example, the
<category> content for Subject would become something like:
The Creative Commons-specific fields build upon existing category/tag support in feeds. Therefore any
cc: field may be specified multiple times if needed. The fields we currently use for refining search results include:
- Subject: cc:subject:
ccLearn's Universal Education Search will be indexing RDFa when pages are crawled, making this our preferred way of encoding machine readable metadata. We believe this will have the broadest possible exposure for current and future software agents.
The subject refers to the actual content in the resource; i.e., what is this resource about? For many resources, more than one subject will be necessary; in this case, specify multiple subject elements. We ask that you try to limit the contents of the subject to only those subjects that are objectively reflective of the entire resource. Other types of categories (opinions, metrics, etc) may have other vocabularies available which are more appropriate.
Specifying Education level
The education level should indicate all levels (student ages) for which the resource is deemed appropriate. The education level should be labeled using the DCT:educationLevel term.
Though we will accept any descriptions that seem appropriate to you, please consider using one of the following schemas:
- primary, secondary, tertiary, adult;
- K,1,2,3,...,20 (where the number refers to the actual grade-level).
You may include equivalent terms as well by specifying more than one
DCT:educationLevel <category>. For example, you might include a
When specifying the language for a resource, the value should be specified as described by RFC-4646. For example,
en for English. To distinguish English (United States) from English (United Kindgom), the language would be specified as
In an Atom 1.0 feed, the language is specified as the
xml:lang attribute of the
content element. Multiple languages in a single entry is not supported.
Embedding license data
Since the licensing of a resource is expected to be conveyed via URL, we can leverage the Atom <link> element. However we must markup the link element so as to identify it as a license URL. This is accomplished with adding the attribute rel="license" to the <link> element. For example:
<link rel="license" href="http://creativecommons.org/licenses/by/3.0/" />
See the complete CC with syndication formats documentation for more information.
Atom 1.0 Example
Here is a sample, one entry Atom 1.0 feed which implements the guidelines above.
<feed xmlns="http://www.w3.org/2005/Atom"> <id>http://oersite.org/cc/</id> <title>OER Aggregation Web Site</title> <updated>2008-01-16T12:00:00Z</updated> <link rel="self" href="http://oersite.org/cc/atom.xml" type="application/atom+xml" /> <author> <name>John Q. Public</name> <email>firstname.lastname@example.org</email> </author> <entry> <id>tag:ocw.org,2007-10-15:/math/101</id> <updated>2007-10-15T12:00:00Z</updated> <link href="http://ocw.org/math/101" /> <title>Math 101</title> <summary>Basic mathematics for 5th graders</summary> <link rel="license" href="http://creativecommons.org/licenses/by/3.0/" /> <category term="cc:subject:Math" /> <category term="dc:educationLevel:5" /> <content type="xhtml" xml:lang="en">The content</content> </entry> </feed>