A METS document conforming to the Greenstone profile contains two Structure Maps
(structMap), which are:
1. A <mets:structMap> for each related sections.
2. A <mets:structMap> for the Whole Document.
This is the heart of a METs documents. Each structMap contains an element with a
TYPE attribute with value "Section" or "Whole Document".
The Structure Map must contain one high level <div> element with a
TYPE attribute with value "Section" or "Document" and a DMDID attribute that
references the dmdSec element.
Each <div TYPE=Section> element will contain more divs if there are
further sub-sectoions within the document. The <div> will contain
one or more File Pointer (<fptr>) elements that reference
File(file) element in the File Group(<fileGrp>) section.