Page 147 - Building Digital Libraries

CHAPTER 6

MODS as a general metadata format, but its need to maintain compatibility
with the library community’s MARC legacy data does raise barriers to the
general mainstream adoption of MODS outside the library community.
Moreover, unlike Dublin Core, MODS is an internal metadata schema
created for the Library of Congress. While the Library of Congress has
accepted a leadership role within the library community and has com-
mitted to growing MODS to meet the needs of that community, it lacks the
large-scale community input and oversight that are found with Dublin Core.
While a large community is currently working with and providing feedback
to the Library of Congress regarding the MODS implementation, the schema
lacks the support of a multi-organizational maintenance body. Rather, MODS
is developed primarily by the Network Development and MARC Standards
Office at the Library of Congress, which may ultimately limit the growth and
scope of the MODS framework as it goes forward. Obviously, within today’s
global environment, a more multinational metadata schema like Dublin
Core presents a number of distinct advantages over a schema developed
primarily for the purposes of a single nation or organization.

METS

Unlike earlier metadata formats discussed within this chapter, METS
(Metadata Encoding and Transmission Standard) is not a metadata format
utilized for the bibliographic description of objects. Dublin Core, MODS,
and even MARC/MARC21XML all share the same primary purpose of
providing a vehicle for the description of bibliographic data. While each
metadata format has its own advantages and disadvantages that may help
a digital repository developer select one metadata format over another,
they all still share the same goal. Ultimately, each of the metadata formats
discussed previously functions to provide various levels of bibliographic
description of a digital object. The same, however, cannot be said of METS.
METS is a very different animal, in that it acts as a container object for the
many pieces of metadata needed to describe a single digital object. Within
a digital repository, a number of pieces of metadata are attached to each
digital object. While the individual who submitted the digital object may
only be responsible for adding information to the bibliographic metadata,
the digital repository itself is generating metadata related to the structural
information of the digital object—that is, assembling information about
the files that make up the entire digital object (metadata, attached items,
etc). METS provides a method for binding these objects together, so that
they can be transferred to other systems or utilized within the local digital
repository system as part of a larger application profile.

History
The history of METS is closely tied to the history of MODS. In the late
1990s, the Library of Congress began exploring avenues for moving
locally created digital collections to an XML-based platform. During this
period of exploration, only two general-purpose XML metadata formats
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