We do need to be careful about confusing the MODS schema, the crosswalks,
the guidelines, etc. It is a common misconception that MARC has been
equated with AACR2, while it is intended to be used with any cataloging
code. We want MODS to be able to accommodate records using AACR2 or any
other cataloging code as well as simpler less controlled records using no
particular cataloging rules. One reason for the guidelines is for those
who do not use a set of rules so that there are still some content rules
for populating the elements. Accommodating all these needs is indeed a
challeng.

In the case of the GMD ([sound recording], etc.), it is the case that the
crosswalk says to put 245$h along with title. As I recall we debated this
early on. This discussion has convinced me that the better approach would
be to put 245$h in <physicalDescription><form> which has an attribute
authority. We could use "gmd" as the authority in these cases, which would
allow us to map from MODS to MARC and be able to put the GMD back in the
title. As you probably have noticed, we took statement of responsibility
(245$c) out of title and put it in a note (labelled as such). This is a
similar situation, where the data doesn't really belong with title.

Since it's a crosswalk change, we can make it without much of an
impact. We will just have to change it in the document on our Web site and
in our stylesheet that does the conversion. A schema change requires of
course revising the schema, which we don't want to do too oftern. We do
plan to do some changes to the schema shortly.

As for indicating cataloging rules, we have thought of that and thought it
was overkill to add. But if others think it important we could consider
putting it in recordInfo in this next set of changes. We already have a
list we use in MARC at:
http://www.loc.gov/marc/relators/reladesc.html#rela040b
I suppose we would say that if the element isn't filled in, no rules are
used or specified.

Rebecca

On Tue, 29 Apr 2003, Karen Coyle wrote:

> At 04:00 PM 4/29/2003 -0700, Roy Tennant wrote:
> >Are we visiting the sins of MARC on MODS? That is, are we once again
> >building a structure with which we can mimic the layout of a card from
> >our card catalog, without thinking critically about what metadata we
> >actually need and how to best encode it?
>
> Are we confusing LC's cross-walk and examples with the capabilities of
> MODS? There's nothing in MODS itself that seems to require the GMD. And of
> course it would never exist in data that doesn't come from a MARC21 record.
>
> Maybe we can make more progress if we parse out this problem into its
> components:
> 1- the MODS structure
> 2- the MARC-to-MODS crosswalk
> 3- [other metadata]-to-MODS crosswalks
>
> Bruce is interested in carrying citation information in MODS, so he
> shouldn't have to be concerned about where AACR2 (library cataloging)
> elements would appear since he won't have them -- unless his citations come
> from a library database, but I have the feeling that's not the usual source
> for his data. Others of us are indeed taking MARC records and turning them
> into MODS, and so we might want to address the crosswalk defined by LC or
> develop our own. If, however, Bruce does get data that originated in a
> library catalog, he is going to see AACR2 cataloging because that's what's
> in those records, just like he may see different citations formats from
> different publications. We can get rid of the GMD, but heading choices will
> be according to AACR2.
>
> I also think we need to separately address the structure of MODS and the
> rules for its content. As you know, this has been the problem area for
> Dublin Core, which defines a rather relaxed structure but does not have
> cataloging rules that define the content of its fields. MARC is not just a
> structure, at least not the way most of us refer to it -- MARC21 implies
> the use of AACR2 to determine exactly what goes into a title or author
> field. What seems to be happening is that some people are assuming the MODS
> also is informed by AACR2, and others have no interest in AACR2 at all. So
> we need get clear about this -- will there be a way to know what rules were
> used to create the MODS record? Do we know now if the record originated as
> a MARC21 record? Is there a way to say that the record was derived from a
> PubMed record structure, or an MLA-formatted bibliography.?
>
> I don't think we should go too far down this road, but I fear that if we
> don't de-couple the record format and the bibliographic rules we'll
> continue to have confusion of purpose.
>
> kc
>