The Metadata Encoding and Transmission Standard (METS) is a recently emergent standard designed to encode metadata for electronic texts, still images,
digitised video, sound files and other digital materials within electronic library collections .
Written in XML schema, METS offers a coherent overall structure for encoding all relevant types of metadata (descriptive, administrative, and structural)
used to describe digital library objects.
The organisation of the standard can be described by the following categories:
- METS Header: the METS Header contains metadata describing the METS document itself, including such information as creator, editor, etc.
- Descriptive Metadata: the descriptive metadata section may point to descriptive metadata external to the METS document (e.g., a MARC record in
an OPAC or an EAD finding aid maintained on a WWW server), or contain internally embedded descriptive metadata, or both. Multiple instances of both
external and internal descriptive metadata may be included in the descriptive metadata section.
- Administrative Metadata: the administrative metadata section provides information regarding how the files were created and stored,
intellectual property rights, metadata regarding the original source object from which the digital library object derives, and information regarding
the provenance of the files comprising the digital library object (i.e., master/derivative file relationships, and migration/transformation information).
As with descriptive metadata, administrative metadata may be either external to the METS document, or encoded internally.
- File Section: the file section lists all files containing content which comprise the electronic versions of the digital object. <file> elements
may be grouped within <fileGrp> elements, to provide for subdividing the files by object version.
- Structural Map: the structural map is the heart of a METS document. It outlines a hierarchical structure for the digital library object,
and links the elements of that structure to content files and metadata that pertain to each element.
- Structural Links: the Structural Links section of METS allows METS creators to record the existence of hyperlinks between nodes in the
hierarchy outlined in the Structural Map. This is of particular value in using METS to archive Websites.
- Behaviour: a behaviour section can be used to associate executable behaviours with content in the METS object.
Each behaviour within a behaviour section has an interface definition element that represents an abstract definition of the set of behaviours
represented by a particular behaviour section. Each behaviour also has a mechanism element which identifies a module of executable code that
implements and runs the behaviours defined abstractly by the interface definition.