Guideline

Metadata standards promote a consistent manner in which metadata is created, managed and exchanged.

They are mutually accepted guidelines developed by professions, industries and/or national and international standard-making bodies. These standards are both human and machine-readable to allow automatic processing and creation of value-added services.

The merging of different pages using metadata can allow us to locate, evaluate and finally access Web resources.

The metadata tags provided by XHTML are widely understood by search engines; at the same time, several search engines (such as Ultraseek, Swish-E, Microsoft's Index Server, Blue Angel Technologies MetaStar and Verity Search 97 Information Server) are using standard metadata like the Dublin Core (DC) metadata sets to create their Web repositories.

Within FAO, the metadata creation tool facilitates the creation of metadata using elements that are supported by the Dublin Core standard as well as extensions that are necessary to describe our agriculture specific resources. These elements, known as the Agricultural Metadata Element Set (AgMES) describe document-like resources, such as Web pages, to facilitate resource discovery in a networked environment.

For example, this is how FAO specific metadata about the creator of a Web page should be encoded within an XHTML page:

<meta name="DC.creator" content="Dave Raggett" />

Notice that we have made use of the prefix (here DC) to indicate that the property is taken as it has been defined by the Dublin Core.

The content of a document can be assigned to the subject property.

<meta name="DC.subject" scheme="AGS.AGROVOC" content="forestry, agroforestry, forest products, food security" />

Notice that here we have used the prefix not only for the name property (DC) but also on the scheme (AGS.AGROVOC). By combining this with the "link" element, machines are able to read and process metadata efficiently.