The METS Editorial Board has a proposed revision to the METS 1 XML Schema. The proposed change will increment the revision number to 1.11. A draft is available from here, https://github.com/mets/METS-schema/tree/Version-1.11. The proposed changes are as follows:
1) The attributes, ORDER, ORDERLABEL, and LABEL, are currently available only for the <div> element. The proposal is to also make these attributes available for the <par>, <seq>, and <area> elements. The ORDER, ORDERLABEL, and LABEL attributes will retain the same semantics they had when used with the <div> element.
ORDER: xsd:integer optional
A representation of the element’s order among its siblings (e.g., its absolute, numeric sequence). For an example and clarification of the distinction between ORDER and ORDERLABEL, see the description of the ORDERLABEL attribute.
ORDERLABEL: xsd:string optional
A representation of the element’s order among its siblings (e.g., “xii”) or of any non-integer native numbering system. It is presumed that this value will still be machine actionable (e.g., it would support ‘go to page ___’ function), and it should not be used as a replacement/substitute for the LABEL attribute. To understand the differences between ORDER, ORDERLABEL and LABEL, imagine a text with 10 Roman numbered pages followed by 10 Arabic numbered pages. Page iii would have an ORDER of “3”, an ORDERLABEL of “iii” and a LABEL of “Page iii”, while page 3 would have an ORDER of “13”, an ORDERLABEL of “3” and a LABEL of “Page 3”.
LABEL: xsd:string optional
An attribute used, for example, to identify a <div>, <par>, <seq>, or <area> to an end user viewing the document. Thus a hierarchical arrangement of the <div> LABEL values could provide a table of contents to the digital content represented by a METS document and facilitate the users’ navigation of the digital object. Note that a <div> LABEL should be specific to its level in the structural map. In the case of a book with chapters, the book <div> LABEL should have the book title, and the chapter <div> LABELs should have the individual chapter titles, rather than having the chapter <div> LABELs combine both book title and chapter title . For further of the distinction between LABEL and ORDERLABEL see the description of the ORDERLABEL attribute.
2) In addition to the three new fixed elements, the Board is also proposing to add xsd:anyAttribute with namespace ##other and processContents lax to these elements. This will allow arbitrary new attributes to be added to these elements to support local needs.
Note that these additions were originally proposed in order to support the rendering of 3D objects which consist of a mesh file and multiple images for the textures that need to be identified individually but rendered in parallel to represent the 3D object, see for example, https://github.com/mets/wiki/blob/master/ChangeRequests/METS%20change%20request%20for%203D%20digitized%20globes.pdf. However, the use of ORDER, ORDERLABEL, and LABEL, might be useful in other use cases where a complex object is represented by use of multiple, nested <par>, <seq>, or <area> elements.
Please respond to this email if you have any comments or questions about this proposal.
Technical co-chair, METS Editorial Board