This is a great example of how hard it is to define "topic of."

In MARC21 data, there are subject headings that are geographical in 
nature (and they are coded as "geographical subject headings" not just 
"subject headings": tag 651, as opposed to tag 650 for "topical 
topics"). Geographical subject headings are used when the primary topic 
of the resource is the geographical area ("California -- History"). You 
can also have geographical facets in subject headings (at least in 
LCSH). That is when there is a main topic ("Dog breeding") with a 
geographical aspect ("in Canada").

There are also places in the record to put geographical info when the 
resource is itself geographical in nature (e.g. a map, which can get 
scale and coordinates).[1] So if your map is coded with geographical 
coordinates for Berkeley, California, can you consider Berkeley, 
California the subject of the map? I think many people would. There is 
also a field that gives hierarchical geographical access to publications 
like newspapers [2] based on where they are published (which is often 
their main topical coverage as well, such as "The San Francisco 
Chronicle").

Note that changing the definition of dc:subject also means re-thinking 
dc:coverage, which has this definition:

"The spatial or temporal topic of the resource, the spatial 
applicability of the resource, or the jurisdiction under which the 
resource is relevant."

Is dc:coverage still to be used for "space or temporal topic"? If it is 
decided that space and temporal topics would be covered by dc:subject 
and dc:coverage is only suitable for "...the spatial applicability of 
the resource, or the jurisdiction under which the resource is relevant" 
then we have to consider whether people will reasonably be able to make 
the distinction between "spatial applicability" and "space... topic." 
Note that such a change also removes the "temporal" aspect of 
dc:coverage, at least as it is now defined.

I think something would be lost by putting geographical names in 
"subject." A bit less is lost if the geographical name is a URI within, 
say, GeoNames, that clearly indicates the "geographicalness" of the 
value. But DC doesn't require URIs. This is also true for temporal 
topics -- which probably actually need their own property apart from 
geographical aspects, but that's water under the bridge.

I think changing the definition of dc:subject would, in fact, have to 
also change the definition of dc:coverage. In addition, it would require 
people to make the difficult distinction between "topically about" and 
"geographically applicable," something that I think is extremely hard 
and therefore not something we should require of people using DC. The 
current situation is not ideal, by any means, but I believe that the 
suggested change would make it worse.

kc

  [1]http://loc.gov/marc/bibliographic/bd034.html
[2] http://www.loc.gov/marc/bibliographic/bd752.html

On 2/24/12 1:20 PM, Thomas Baker wrote:
> Dear all,
>
> Since 2006, the usage "comment" for the definition of dc:subject (and since
> 2008, dcterms:subject) has included the following sentence [1,2,3]:
>
>      To describe the spatial or temporal topic of the resource, use the Coverage
>      element.
>
> The intent was to provide guidance on when to use Coverage:
>
>      The spatial or temporal topic of the resource... [5]
>
> and when to use Subject, which had a clearly overlapping definition:
>
>      The topic of the resource. [6]
>
> I recently had a chat about this with Gordon, who points out -- and I'll
> let him elaborate -- that current notions of subject ("aboutness") do not
> treat "spatial or temporal" topics separately from any other topics.
>
> In my reading of meeting notes and decision documents from the time (see
> "Background" below), the addition of the sentence quoted above to the Comment
> for Subject was not intended as a clarification of the formal definition of
> Subject, but rather as guidance about "which element to use" at a time when
> people commonly wanted to use the fifteen elements in non-overlapping ways.
>
> If this usage guideline is now unhelpful, should it be removed (after due
> process of course)?
>
> Tom
>
>
> ----------------------------------------------------------------------
> Background
>
> The sentence from the Comment for Subject, quoted above, was added at the time
> the definition of Coverage was changed from:
>
>      The extent or scope of the content of the resource. [4]
>
> to:
>
>      The spatial or temporal topic of the resource, the spatial applicability
>      of the resource, or the jurisdiction under which the resource is
>      relevant. [5]
>
> as explained in [3].  This brought the definition of Coverage very close to the
> definition of Subject:
>
>      The topic of the resource. [6]
>
> At the time, it was widely felt that Dublin Core elements should not overlap in
> meaning; indeed, it was not until 2008 that Creator was declared to be a
> subproperty of Contributor [7].  As near as I can tell, then, the sentence
> quoted above was added to the usage comment for Subject in an effort to provide
> guidance to users about "which element to use" in a case where two definitions
> clearly overlapped.
>
> [1] http://dublincore.org/documents/dcmi-terms/#subject
> [2] http://dublincore.org/documents/dcmi-terms/#terms-subject
> [3] http://dublincore.org/usage/decisions/2006/2006-03.dcmes-changes.shtml
> [4] http://dublincore.org/documents/2006/08/28/dcmi-terms/#coverage
> [5] http://dublincore.org/documents/2006/12/18/dcmi-terms/#coverage
> [6] http://dublincore.org/documents/2006/12/18/dcmi-terms/#subject
> [7] http://dublincore.org/usage/decisions/2008/dcterms-changes/#sect-3
>

-- 
Karen Coyle
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m: 1-510-435-8234
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