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Web Feed Generator

Create low-maintentance news feeds for your next Web project.

Metadata questions

This screen is part of a Web Feed Reference section for the Web Feed Generator. Please ask us if you cannot find the answer to your question.

Q:What is metadata?

A: Metadata is a collective name for higher level information about a Web page, a person, a book or any other item, which tells you something more about it. A library catalogue is an example of metadata; each record tells you the title, author and subject of a book. Other examples include a person's social security code, telephone number or payroll identifier.

Metadata are used to classify and index things, so people can find out about them quickly and easily. By recording category, name and time data, it becomes possible to search for items that are associated with a particular topic, whose names contain a certain word, or were created on a specific date.

Metadata about Web pages are usually recorded in meta elements, as below, and a single Web page may contain many different metadata statements. 

<meta name="subject"
 content="Norwich City Football Club"/>

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Q:What is RDF?

A: RDF is a technical term for a way of describing things in a form that can be processed and interpreted by computers. Descriptions are stated in a formal way that labels an item with a named characteristic and the detail of the characteristic. For instance, a book may have these characteristics and details:

  • title: On The Origin Of Species By Means Of Natural Selection
  • subject: Evolutionary biology
  • author: Charles Darwin

RDF descriptions can seem very laborious because each characteristic is set out in its own right. Instead of saying "It was a dark and stormy night", an RDF description might say:

  • The illumination that night was "dark".
  • The weather that night was "stormy".

RDF might also tell you the criteria by which the night was classified as "stormy", by referring to the Beaufort scale for example.

The formality of the RDF scheme makes it possible for computer systems to read, compare and interpret these descriptions and work out relationships between them. To say that Charles Darwin is the author of one book may enable us to identify other books by Charles Darwin. If we find letters written by Charles Darwin on the subject of "Evolutionary biology", we might deduce that he is also the author of "The Origin Of Species".

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Q:What is XML?

A: XML is a technical term for the feed format created by the Web Feed Generator. XML is a way of marking text so that its meaning is distinct and information can be picked out and processed by computer software.

XML is like a set of Russian dolls where text can be nested at each level. The text in a book is in chapters, a chapter contains paragraphs, inside paragraphs there may be sections of emphasis.

XML can also be thought of as a tree representation of data; in a large corporation there may be several divisions or branches, each branch may have departments and the staff are like leaves on the tips of the finest branches. 

<book>
  <chapter id="Chapter1">
    <title>
      Chapter 1
    </title>
    <paragraph>
      This chapter starts with an <emphasis>important</emphasis> example ...
    </paragraph>
    <paragraph>
      ...
    </paragraph>
  </chapter>
  <chapter>
    <title>
      Chapter 2
    </title>
    <paragraph>
      This chapter refers to <link target="Chapter1">chapter 1</link> ...
    </paragraph>
  </chapter>
</book>

XML provides a standard format for recording information in this way, but it does not say how the parts should be named and which go inside another. This means that different types of XML can be designed for special purposes, yet still conform to the fundamental nesting and branching rules.

Web pages can be written in a type of XML called XHTML. The news feeds provided by Metacentric are a type of XML called RSS, and the metadata feeds are known in the jargon as RDF. Ultimately, these details are far less important than what these services actually do.

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Q:What is the Semantic Web?

A: The Semantic Web is a vision of the way the Internet may develop in the future that will help you discover information more precisely and intelligently, with software that has a better understanding of what you are looking for and where to find it. The technical framework for building the Semantic Web is being designed and promoted by the World Wide Web Consortium, which helps steer the development of the Internet at large, and is closely allied to various schemes for representing and interpreting metadata.

The study of semantics is to do with the meaning of words and the relationships between them. One of the aims of the Semantic Web is to define information on the Web in ways that have distinct meanings, which can be interpreted and compared by computer software. By establishing a common framework to indicate the meaning of metadata, search engines will be able to apply logical reasoning to the queries they run.

Since metadata are of such significance to the Semantic Web, our reliance and trust in specific sources of information is a critical factor. Whether or not you regard a newspaper, public institution or friend of a friend as a reliable source is a matter of judgement and opinion. The way we manage that network of trust is fundamental to the Semantic Web.

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Q:How can I include the area of jurisdiction in my metadata?

A: The Web Feed Generator is designed to pick up any Dublin Core metadata in the meta elements of your Web page. All you need to do is ensure the jurisdiction data is included, as below. 

<meta
  name="DC.Coverage.jurisdiction"
  content="Australia"
  lang="en" xml:lang="en" />

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Q:What is Dublin Core?

A: Dublin Core is the name of an international organisation that provides guidelines on the use of metadata. You may also hear the phrase Dublin Core Metadata Initiative (DCMI), which is the name of the main project the group is responsible for. The aim of the Dublin Core organisation is to design and define a set of metadata elements that can be used to classify a broad range of information on the Web, and other data systems.

The Dublin Core group has defined a standard set of metadata elements, the Dublin Core Metadata Element Set, which attach specific meaning and purpose to the plain English labels for the terms listed below. Some labels are more obvious than others. In each case, the resource is the thing the metadata describes, such as a Web page.

  • Title: A name for the resource.
  • Creator: The main person or group that created the resource.
  • Subject: The classified topic of the resource.
  • Description: An explanation of what the resource is about.
  • Publisher: The person or organisation that published the resource.
  • Contributor: A person or group that helped make the resource.
  • Date: A date to do with the existence of the resource.
  • Type: The physical nature or genre of the resource.
  • Format: The physical medium of the resource.
  • Identifier: A unique reference to the resource.
  • Source: A reference work from which the resource is derived.
  • Language: The main language of the resource.
  • Relation: A reference to another resource associated with this.
  • Coverage: The extent of the resource's relevance over time and physical space.
  • Rights: Information about the ownership and distribution rights for the resource.

The Dublin Core group also define a more precise set of terms, known as qualifiers, that can be used to make the meaning of the primary elements more distinct. Defining specific meanings for these metadata terms and their qualifiers means they can be catalogued and interpreted by software systems in more constructive ways.

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Q:What is a URI?

A: URI stands for Uniform Resource Identifier and is essentially the same as a Web address or URL. One subtle difference is that URIs do not necessarily have to point to a real Web document, they may only act as a marker for something else.

URIs are used to uniquely identify a resource in formal metadata schemes. They may refer to something that is being described, such as a Web page, or a particular metadata label that is used to describe it.

Q:What metadata schema do you support?

A: Our Web Feed Generator service supports the Dublin Core Metadata Element Set and qualified terms. You will find it also adapts to simple extensions of these schema prefixed by DC. or DCTERMS.

If you require support for different metadata schema or more complex application profiles, please contact us with your requirements.

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Q:Why isn't my DCMIPoint data included?

A: DCMIPoint metadata should be labelled DCTERMS.Point, not DCTERMS.DCMIPoint. 

<meta name="DC.Coverage" scheme="DCTERMS.Point"
  content="east=148.26218; north=-36.45746; elevation=2228; name=Mt. Kosciusko" />
Q:Why isn't my DCMIPeriod data included?

A: DCMIPeriod metadata should be labelled DCTERMS.Period, not DCTERMS.DCMIPeriod. 

<meta name="DC.Coverage" scheme="DCTERMS.Period"
  content="start=2004-10-11;end=2006-01-11;scheme=W3CDTF" />
Q:Why isn't the MeSH scheme included?

A: It is, but the scheme label is DCTERMS.MESH in capitals, not DCTERMS.MeSH with a lower case "e". 

<meta name="DC.Subject" scheme="DCTERMS.MESH"
  content="Angiostatins" />
Q:My URI should be an rdf:resource attribute!

A: You must specify the Dublin Core qualified term "URI" in the meta scheme attribute for the Web Feed Generator to recognise a URI resource. 

<meta name="DC.Relation" scheme="URI"
  content="http://remote.example/reference.html" />
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