APPENDIX:
STRUCTURAL METADATA NOTES
- Structural metadata is metadata that describes the types, versions,
relationships and other characteristics of digital materials" (Arms,
Blanchi, and Overly 1997).
- Structural metadata [for digital objects for individual versions]
includes other metadata associated with the specific version. It
includes fields for description, owner, handle of meta-object,
data size, data type (e.g., "jpg"), version number, description,
date deposited, use (e.g., "thumbnail"), and the date
of the last revision" (Arms, Blanchi, and Overly 1997).
- Structural metadata [for the meta-object] is the metadata that
applies to the original photograph and to all of its versions.
It includes a description, the owner, the number of versions, the
date deposited, the use ("meta-object"), and the date
of last revision. If bibliographic information were to be included,
it would be added to this part of the meta-object" (Arms,
Blanchi, and Overly 1997).
- Schema definitions are of course very basic forms of metadata.
We refer to a schema definition language as structural metadata,
and distinguish it from the representation of semantics, meaning,
and purposefor which we would use the term semantic metadata. In
general, we would like a single metadata model to encompass structure
and semantics, and, preferably capable of representing most data
models" (Morgenstern 1997).
- Looking at the larger picture, there are three type of "metadata" which
have been identified by the National Digital Library Project of
the U.S. Library of Congress as being relevant to digital collections,
namely: (1) descriptive metadata (such as MARC cataloguing records,
finding aids, or locally developed practices for describing what
the images are about); (2) structural metadata (the information
that ties the images to each other to make up a logical unit such
as a journal article or archival folder); (3) administrative metadata
(what allows the repository to manage the digital collection, such
as scan date and resolution, storage format and filename)" (Gartner
1997).
- The [Metadata Working] Group worked with the broadest definition
of metadata; that is, data about data. It was agreed that the purpose
of metadata was (a) to help the user discover or locate resources;
(b) to describe those resources in order to help users determine
whether the resources would be useful; and (c) to provide physical
access to the electronic resource. In the broadest terms, metadata
can be characterized as either descriptive or structural. Descriptive
metadata, such as a MARC record, provides intellectual access to
a work while structural metadata, such as a TIFF header, can be
queried and operated on to provide physical access and navigational
structure to a document-like object. Much of the discussion in
the MWG meetings focused on descriptive metadata; however, a subgroup
of the MWG and the Full-Text Working Group met to identify and
assess the structural and descriptive metadata which underlies
the various scanned image projects at Cornell" (World Wide
Web Working Group, Cornell University Library, 1996).
- [Cornell University Library] should embed structural metadata
within full-text resources to enable direct access to special document
features, such as tables of contents, title pages, indices, etc.,
and also correlate image sequence numbers to actual page numbers
of the document to enhance navigation within "loosely-bound" electronic
documents (e.g., individual scanned image files for pages of a
document)" (Cornell University, Distillation of the Working
Group Recommendations, 1996).
- Structural metadata is used for creation and maintenance of the
information warehouse. It fully describes information warehouse
structure and content. The basic building block of structural metadata
is a model that describes its data entities, their characteristics,
and how they are related to one another. The way potential information
warehouse users currently use, or intend to use, enterprise measures
provides insight into how to best serve them from the information
warehouse; i.e., what data entities to include and how to aggregate
detailed data entities. A Visible Advantage information warehouse
data model provides a means of documenting and identifying both
strategic and operational uses of enterprise measures. It also
provides the capability to document multi-dimensional summarization
of detail data" (Perkins 1997).
- Structural metadata identifies the system of record for all information
warehouse data entities. It also fully describes the integration
and transformation logic for moving each information warehouse
entity from its system of record to the information warehouse.
In addition, structural metadata defines the refreshment schedule
and archive requirements for every data entity" (Perkins 1997).
- Structural dataThis is data defining the logical components of complex or compound objects and how to access those components. A simple example is a table of contents for a textual document. A more complex example is the definition of the different source files, subroutines, data definitions in a software suite" (Lagoze, Lynch, and Daniel 1996).
