[tdwg-content] What is dwc:basisOfRecord for?

[John Wieczorek]

Sorry for the delay. Just back from Tanzania.

The basisOfRecord is meant to classify the content of the resource (record)
as specifically as possible, in the sense of how the contributor of the
resource intended for it to be used. The value of the basisOfRecord should
be based on the most specific Class (a DwCtype) of information the resource
(record) represents. Thus, if an Occurrence record was supported by a
PreservedSpecimen as evidence, then the record containing the specimen
information should have PreservedSpecimen as the basisOfRecord. It's still
an Occurrence, because PreservedSpecimen is a formal refinement of an
Occurrence in the RDF sense of <rdfs:subClassOf  rdf:resource="
http://rs.tdwg.org/dwc/dwctype/Occurrence"/>. So, your example record should
have PreservedSpecimen as its basisOfRecord, and that means it is an
Occurrence record, because all PreservedSpecimen records are.

Why have the Occurrence type? For consistency. We have one DwCType for every
DwC (or borrowed Dublin Core) Class. Yet, we are much more interested in the
peculiarities of Occurrences than we are in different types of, say, Events,
because of the implications for their use. So we have gone to the effort to
create several subclasses of Occurrence based on demonstrated requirements.

Why have a basisOfRecord at all? To assist the data consumer to know the
ways in which the resource (record) might be used. Without the basisOfRecord
term, the detailed content of the records would have to be assessed to
assert what the record was about.

Steve said,
"But realistically, any such table that includes multiple token types isn't
going to work very well."

and,

"basisOfRecord also has no use for Occurrences that have several tokens.
Which of the several tokens are we saying is the "basis" of the record?"

Why not? Nothing in Darwin Core says that you can't create a schema in which
an Occurrence is supported by multiple "tokens", each with its own
basisOfRecord. Of course, Simple Darwin Core doesn't support that, and maybe
that's where these perceptions of inadequacy come from.


On Wed, Oct 27, 2010 at 10:34 AM, Steve Baskauf <
steve.baskauf at vanderbilt.edu> wrote:

>   occurrenceID
>  recordedBy
>  other Occurrence terms
>  preparations
>  other specimen-related terms
>  basisOfRecord
>   http://herbarium.org/12345
>  Joe Curator
>  ...
>  pressed and dried
>  ...
>  ???
>
> OK, above is an example of a database record that I would consider
> typical.  The manager has flattened the general model we have been
> discussing to merge the Occurrence resource with the token resource since in
> his/her database no occurrence has any token other than a single specimen.
> So what is the value for basisOfRecord: Occurrence or PreservedSpecimen?
> What I'm getting at here is that there seems to be ambiguity as to whether
> we intend for basisOfRecord to represent the type of the record (which in
> this case I would say is Occurrence) or the type of the token on which the
> record is based (which in this case is PreservedSpecimen).  In that lengthy
> discussion that happened last October, there was discussion of having the
> proposed recordClass represent the type of the overall record (Occurrence,
> Event, Location, etc.) and basisOfRecord representing the type of the token
> or evidence on which an Occurrence record is based (PreservedSpecimen).  I'm
> not sure what is intended now.
>
> I see this lack of clarity as being a consequence of the general blurring
> of the distinction between the Occurrence and the "token".  I feel like
> there is a general consensus that we need to tighten up our definitions
> regarding Occurrences and their evidence even if some people will prefer to
> continue using the "flattened" approach to Occurrences and their tokens
> illustrated above (which they are entitled to do).  I don't have a problem
> with the various types that you've listed below.  The problem is that I
> don't think the definition of basisOfRecord makes clear how it
> (basisOfRecord) should apply - the definition just says "the specific nature
> of the data record" and that the controlled vocabulary of the Darwin Core
> Type Vocabulary should be used.  Since the Type Vocabulary includes all of
> the classes (Event, Location, Occurrence, etc.) in addition to the types of
> "tokens", I believe that some users might think that making a statement like
> basisOfRecord="Event"
> is correct.  If we intend for basisOfRecord to ONLY apply to Occurrences,
> and for basisOfRecord to ONLY have as valid values the types that apply to
> tokens (i.e. PreservedSpecimen, LivingSpecimen, HumanObservation), then we
> should say so explicitly in the definition.  If we do not say this, then we
> end up with the kind of ambiguity that I illustrated above.  basisOfRecord
> ends up getting "overloaded" to represent general classes of records and
> also to represent the types of tokens.
>
> In addition, I'm not entirely convinced that basisOfRecord actually has any
> use at all.  It seems to be intended for situations such as I've illustrated
> above where a database table has rows that could contain occurrences
> documented with different types of tokens.  Ostensibly, basisOfRecord is
> needed to tell us the type of the token.  But realistically, any such table
> that includes multiple token types isn't going to work very well.  For
> example, if the table includes Occurrences that are documented by specimens,
> images, and no token/memories (i.e. HumanObservations), then it's going to
> have a bunch of columns that are empty for any particular record.  The
> specimens rows won't have anything in the image term columns, the images
> won't have anything in the specimen term columns, and the human observations
> won't have anything in either the specimen or image term columns.  I think
> most database managers would just include the terms that apply to all
> Occurrences in the Occurrence table and then use identifiers to link
> separate tables for the metadata terms that are specific to the various
> types of tokens.  basisOfRecord also has no use for Occurrences that have
> several tokens.  Which of the several tokens are we saying is the "basis" of
> the record?
>
> So again, my basic question is not so much about the various types and
> subtypes to which we can refer, but specifically how the basisOfRecord term
> is to be used.
>
> Steve
>
> Blum, Stan wrote:
>
> Steve,
>
> I'm wasn't involved in those final discussions of dwc:basisOfRecord and the
> type vocabulary, but I don't see a difficulty.  The Dublin Core type
> vocabulary includes the following:
>
>     Collection
>     Dataset
>     Event
>     Image
>     InteractiveResource
>     MovingImage
>     PhysicalObject
>     Service
>     Software
>     Sound
>     StillImage
>     Text
>
> The Darwin Core types extend that with the three additional types, and with
> Occurrence being further subtyped with those different kinds of Occurrences.
>
>     Location
>     Taxon
>     Occurrence
>         PreservedSpecimen
>         FossilSpecimen
>         LivingSpecimen
>         HumanObservation
>         MachineObservation
>         NomenclaturalChecklist
>
> Data publishers/providers should categorize their Occurrence data as one of
> those subtypes (or perhaps another subtype that wasn't included in that
> list).  It's up to the consumer to decide which kind of Occurrence subtypes
> are appropriate for a particular use.
>
> Could you give examples of the inconsistent use of values in basisOfRecord ?
>
> Also note, John W. is traveling at the moment.  Markus might be able to
> provide additional thoughts.
>
> -Stan
>
>
>
>
> On 10/25/10 10:34 PM, "Steve Baskauf" <steve.baskauf at vanderbilt.edu> <steve.baskauf at vanderbilt.edu> wrote:
>
>
>
>  OK, I know that this sounds like a stupid question, but I really want
> somebody who was involved in the development and maintenance of the
> current DwC standard to tell me how the term dwc:basisOfRecord is
> supposed to be used (not what it IS - I've seen the definition athttp://rs.tdwg.org/dwc/terms/index.htm#basisOfRecord)?  I would like for
> the answer of this question to be separated from the issue of what the
> Darwin Core type vocabulary
> (http://rs.tdwg.org/dwc/terms/type-vocabulary/index.htm) is for.
>
> I re-read the lengthy thread starting withhttp://lists.tdwg.org/pipermail/tdwg-content/2009-October/000301.html
> which talked a lot about basisOfRecord and its relationship to other
> ways of typing things.  I don't want to re-plough that ground again, but
> I couldn't find the post that stated what the final decision was. I
> remember that there was a decision to NOT create the recordClass term
> which was the subject of much discussion.
>
> I guess my confusion at this point is with the inclusion of both
> "Occurrence" and "PreservedSpecimen" in the same list.  Let's say that I
> have a flat database where I include metadata about the Occurrence (such
> as dwc:recordedBy) and the specimen (such as dwc:preparations) in the
> same line.  What is the basisOfRecord for that line?  I would guess that
> the "basis of the record" was the specimen.  But the line in the record
> also represents an Occurrence.  It seems like there is a lack of clarity
> as to whether basisOfRecord is supposed to indicate the type of the
> record (which would be an Occurrence record) or whether it's supposed to
> indicate the kind of evidence on which the record is based (which would
> be PreservedSpecimen).  There have been various times where I've seen a
> database record that includes basisOfRecord and it seems to be
> inconsistently applied.
>
> I can see how the Darwin Core type vocabulary could be useful - it
> pretty much lays out useful values that one could give for rdfs:type.
> But basisOfRecord as a term is confusing me.
>
> Steve
>
>
>
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> .
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>
>
>
> --
> Steven J. Baskauf, Ph.D., Senior Lecturer
> Vanderbilt University Dept. of Biological Sciences
>
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