Workbook on Digital Private Papers > Administrative and preservation metadata > Using METS for the preservation and dissemination of digital archives
Using METS for the preservation and dissemination of digital archives
Structure of a METS file
Root element The root element <mets> provides the overall container for the information being stored or transmitted, which is held within the seven sections listed above. This element can contain a number of attributes; all of these are optional, although the METS Primer and Reference Manual strongly recommends using the OBJID attribute, which is the primary identifier assigned to the METS document as a whole and operates to tag the METS document to external systems.
The root element can also contain the namespaces (xmlns) and schema instance locations (xsi) of the external standards referenced in the METS record. This is shown in the example AIP METS root below, which contains: descriptive metadata encoded in both Dublin Core and the Metadata Object Description Schema (MODS); administrative metadata encoded in TextMD, METSRights and PREMIS; and XML Linking Language (xlink) for linking between the File Section and Structural Map.
Example:
Here, the OBJID attribute is used to record the identifier that will be assigned to the object, perhaps by the digital repository software (e.g. Fedora). There is also a label to identify the resource to human users, which includes the subject line of the email.
METS Header <metsHdr> The METS Header contains some basic information describing the METS document itself. This might include details of the document author or any other agents who have played a role in the METS document (e.g. editor); this does not relate to agents who are associated with the digital object described by the METS document. The <metsHdr> element can also include dates and times of creation and modification; and any alternative identifiers for the document.
Example:
