Hello all,
As a data provider I must admit that I am somewhat alarmed by the potential for
having to provide
multiple metadata representations for thousands (millions) of datasets. I noted
in John Weatherley's
seminar on OAI metadata harvesting that the original source materials were
DCXML files (see
http://dublincore.org/documents/2000/07/14/dcmes-xml/ for a discussion and
DTD). I could easily
imagine a situation where I had to create and maintain these files and a
parallel set for FGDC
representations. This is, of course, relatively straightforward in a world of
static metadata. DC
seems much more static than FGDC, so maybe this is not a huge problem. In a
dynamic metadata
situation where data providers, data managers, or data processing systems are
interacting with the
metadata on essentially random time schedules, seems like it could turn into a
massive file
management headache. BTW, John Caron's seminar suggested that I was going to
need a bunch of other
XML files hanging around to define collections. This only adds to the problem.
My approach to avoiding this problem is to try to produce multiple metadata
representations from a
single source (in my case a relational database). The content of that database
is essentially FGDC,
although I expect that it will soon migrate to ISO 19115. What's important
about this is that it is a
"fatter" standard (it has more stuff). The desire to have more stuff is what
led me to agree with
Jeff's earlier e-mail suggesting that it might be difficult to recover from
starting small. In that
case, the problem Jeff and Stefano have discussed becomes one of revealing
different subsets of
information from the database in response to different requests.
In any case, I was driven to explore the DC-FGDC crosswalk in the hope that I
could easily create DC
from FGDC (what the heck, it's the day after Christmas and I'm at work!). I was
interested to see
that this crosswalk was not referenced in the big list of crosswalks
(http://www.ukoln.ac.uk/metadata/interoperability/). Is there an obvious reason
for that? My initial
efforts are in the attached file. It looks to me like this crosswalk is rather
straightforward. The
most serious omission is the identifier field. As far as I know, FGDC does not
include this concept,
unfortunately. Could be added as an extension. I also think OGC is working on
an interesting approach
to unique identifiers.
This crosswalk may raise some interesting questions about the list of metadata
elements Ben presented
(http://www.smete.org/nsdl/workgroups/standards/current_element_set.html BTW,
the definition of the
identifier element is broken in that list). When one follows the crosswalk to
FGDC land, one many
times lands in the middle of a section that has a bunch of required elements
that are not included in
DC. This, of course, makes going from DC to FGDC impossible, but it raises the
question of whether
NSDL might want to beef up this list. What good are keywords from a controlled
vocabulary if you
don't know what controlled vocabulary it is? or identifiers from a specific
context if you don't know
what context it is?
I am a real neophyte in this business, so I could be making some simple errors.
In any case, it is
also a rough draft!
Happy New Year to all!
Ted Habermann
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<title>DC- FGDC Crosswalk</title>
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<h1 style='color:black;font-family:Arial;font-size:14.0pt;font-weight:800;
font-style:normal'>DC- FGDC Crosswalk</h1>
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<td height=21 class=xl226945 width=425 style='height:15.75pt;width:319pt'>DC
Element</td>
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???</td>
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<td height=17 class=xl236945 width=425
style='height:12.75pt;width:319pt'>Title:
A name given to the resource.</td>
<td class=xl256945>1.1.8.4 Title -- the name by which the data set is
known.</td>
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<td height=51 class=xl236945 width=425
style='height:38.25pt;width:319pt'>Creator:
An entity primarily responsible for making the content of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>1.1.8.1 Originator -- the
name of an organization or individual that developed the data set. If the
name of editors or compilers are provided, the name must be followed by
"(ed.)" or "(comp.)" respectively.</td>
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<td height=34 class=xl236945 width=425
style='height:25.5pt;width:319pt'>Subject:
Typically, a Subject will be expressed as keywords, key phrases or
classification codes that describe a topic of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>1.6.1.2 Theme Keywords<br>
1.6.3.2 Stratum Keywords</td>
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<td height=51 class=xl236945 width=425
style='height:38.25pt;width:319pt'>Description:
An account of the content of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>1.2.1 Abstract -- a brief
narrative summary of the data set.<br>
1.2.2 Purpose -- a summary of the intentions with which the data set was
developed.<br>
1.2.3 Supplemental Information -- other descriptive information about the
data set.</td>
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<td height=34 class=xl236945 width=425
style='height:25.5pt;width:319pt'>Contributor:
An entity responsible for making contributions to the content of the
resource.</td>
<td class=xl236945 width=533 style='width:400pt'>2.5.1 Source Information --
list of sources and a short discussion of the information contributed by
each.</td>
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<td height=51 class=xl236945 width=425
style='height:38.25pt;width:319pt'>Publisher:
An entity responsible for making the resource available</td>
<td class=xl236945 width=533 style='width:400pt'>1.1.8.8.2 Publisher -- the
name of the individual or organization that published the data set.<br>
6.1 Distributor -- the party from whom the data set may be obtained.</td>
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<td height=34 class=xl236945 width=425 style='height:25.5pt;width:319pt'>Date:
A date associated with an event in the life cycle of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>1.1.8.2 Publication Date --
the date when the data set is published or otherwise made available for
release.</td>
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<td height=34 class=xl236945 width=425 style='height:25.5pt;width:319pt'>Type:
The nature or genre of the content of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>8.6 Geospatial Data
Presentation Form -- the mode in which the geospatial data are represented.
Potential Controlled Vocabulary Problems.</td>
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<td height=17 class=xl236945 width=425
style='height:12.75pt;width:319pt'>Format:
The physical or digital manifestation of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>6.4.2.1.1 Format Name -- the
name of the data transfer format.</td>
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style='height:25.5pt;width:319pt'>Identifier:
An unambiguous reference to the resource within a given context.</td>
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style='height:25.5pt;width:319pt'>Source:
A Reference to a resource from which the present resource is derived.</td>
<td class=xl236945 width=533 style='width:400pt'>1.1.8.11 Larger Work
Citation -- the information identifying a larger work in which the data set
is included.</td>
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<td height=17 class=xl236945 width=425
style='height:12.75pt;width:319pt'>Language:
A language of the intellectual content of the resource.</td>
<td class=xl236945 width=533 style='width:400pt'>1.2.3 Supplemental
Information -- other descriptive information about the data set.</td>
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<td height=68 class=xl236945 width=425
style='height:51.0pt;width:319pt'>Relation:
A reference to a related resource. These relations are expressed by
qualifiers: IsVersionOf, HasVersion, IsReplacedBy, Replaces, Requires,
IsPartOf, HasPart, IsReferencedBy, IsFormatOf, HasFormat</td>
<td class=xl236945 width=533 style='width:400pt'>Many of these relations
could end up being expressed as parts of a lineage chain in section 2.5.
Others would be expressed as part of the Larger Work Citation (1.1.8.11).</td>
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<td height=68 class=xl236945 width=425
style='height:51.0pt;width:319pt'>Coverage:
The extent or scope of the content of the resource. Coverage will typically
include spatial location (a place name or geographic coordinates), temporal
period (a period label, date, or date range) or jurisdiction (such as a named
administrative entity).</td>
<td class=xl236945 width=533 style='width:400pt'>1.6.2.2 Place Keywords<br>
1.6.4.2 Temporal Keywords</td>
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<td class=xl236945 width=533 style='width:400pt'>1.7 Access Constraints --
restrictions and legal prerequisites for accessing the data set. These
include any access constraints applied to assure the protection of privacy or
intellectual property, and any special restrictions or limitations on
obtaining the data set.<br>
1.8 Use Constraints -- restrictions and legal prerequisites for using the
data set after access is granted. These include any use constraints applied
to assure the protection of privacy or intellectual property, and any special
restrictions or limitations on using the data set.</td>
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