Grouping related files

A sequence of file group elements <fileGrp> can be used group the digital files comprising the content of a METS object either into a flat arrangement. In the case where the content files are images of different formats and resolutions, for example, one could group the image content files by format and create a separate <fileGrp> for each image format/resolution such as:

• one <fileGrp> for the thumbnails of the images
• one <fileGrp> for the higher resolution JPEG images
• one <fileGrp> for the archival TIFF images

Meanwhile, the <structMap> element can be used to link together the different representations of the same intellectual content.

A <fileGrp> may contain zero or more <file> elements. As described below, a <file> element may contain <FLocat> pointers to one or more external content files via a URI and/or may itself contain the file content as XML or binary data using the <FContent> element.

Nested (hierarchical) arrangement with file groups is not allowed, since complex structures are meant to be described in the Structural map section <structSec>.

Example

The following METS fragment represents the page images of a book that are in TIFF format. The following METS fragment represents the TIFF page images of a book:

<mets:mets xmlns:mets="http://www/loc.gov/METS/v2"
 xmlns:xsi="http://www/w3/org/2001/XMLSchema-instance"
 xsi:schemaLocation="http://www.loc.gov/METS/v2
 http://www.loc.gov/standards/mets/mets.xsd" OBJID="ark:/13010/kt9s2009hz"
 LABEL="Martial Epigrams">
  ...
  <mets:fileSec>
    <mets:fileGrp ID="TIFF_GRP01" USE="ARCHIVAL">
      ...
  </mets:fileSec>
  ...

There may be other <fileGrp>s that contain JPEG or PNG manifestations of the same pages.