[tdwg-content] practical details of recording a determination What is an Occurrence?
arlin at umd.edu
Tue Oct 19 18:15:01 CEST 2010
On Oct 19, 2010, at 11:35 AM, Steve Baskauf wrote:
> I've tried to recreate your diagram at
Note that the visible label gives the correct URL (http://bioimages.vanderbilt.edu/pages/rich-diagram1.gif
), but for some reason its linked to the wrong URL-- so don't click
it, just cut & paste it.
> Please correct me if I didn't get it right. My arrow-drawing
> utility put the arrow heads on the other end of the lines, but I
> think the arrows still maintain the "many to one" relationships you
> were trying to represent. I also replaced eventTime with eventDate
> since the latter is a broader term that also can include the time.
> In principle, I agree with this diagram to the left of
> taxonNameUsage completely. (I still need clarification about a few
> things on the right end.) My main reason for using determination as
> a term rather than identification is because it is not ambiguous to
> refer to the person doing the identifying as the determiner, whereas
> referring to that person as the "identifier" creates confusion
> between that person and the identifying string for resources (as in
> "persistent identifier"). So if we agree that determination,
> annotation, and identification all mean the same thing (namely an
> instance of the dwc:Identification class), I'm happy to just use the
> term "identification". For the person doing it, I guess
> dwc:identifiedBy would be the best term although it's a bit awkward
> in regular speech so I may slip and still say "determiner".
> Although I agree in principle that there can be many occurrences at
> an Event and many events at a Location, I think there are two
> practical reasons why it may be better to assign separate eventDate
> and Location metadata to each Occurrence. The first is that it
> makes the database structure simpler. As Markus has already noted,
> we really would prefer for the database to be as "flat" as
> possible. When I look at the terms listed in the DwC term page (http://rs.tdwg.org/dwc/terms/index.htm
> ) under Event, the most important one that I see which everyone
> should be providing is eventDate. The rest I would pretty much
> consider optional and as a shortcut Rich's diagram could be
> collapsed to make them direct properties of the Occurrence. The
> second reason involves the practical matter of defining a Location.
> I will note that my thinking about this has been deeply influenced
> by a previous discussion on the topic from 2008-2009 summarized at http://www.sernec.org/files/summary-of-discussion.pdf
> on p.78-84. I don't think most people will want to wade through
> all of that text, so I'll just sum it up here. Somebody (I think it
> might have been Debbie Paul at Morphbank) suggested to me that we
> really have an intrinsically globally unique identifier for
> Location. It's the combination of dwc:decimalLatitude and
> dwc:decimalLongitude along with dwc:coordinateUncertaintyInMeters to
> establish precision and dwc:geodeticDatum to establish the reference
> system. (If we like geo:lat and geo:long, then the reference system
> is implied and we are down to three terms to unambiguously define a
> Location and its uncertainty. For the benefits of humans, a
> Locality description is probably also beneficial. Also, elevation
> and depth might be provided, although at least in theory elevation
> could be calculated with a sufficiently good digital elevation
> model). I will grant that we don't have this information for a lot
> of old records, but based on the massive efforts to geolocate
> specimens, I would say it's pretty clear that this is what we would
> like to have if we could get it. I certainly hope that there aren't
> any serious collectors, observers, and live organism photographers
> who aren't by this point trying to record this information as they
> establish new Occurrence records. If you look at all of the
> Location terms on the dwc list, most of the other terms are either
> concessions to the fact that we don't have what we want (e.g. the
> "verbatum" terms), things we could generate using a computer program
> if we were clever (like stateProvince, county, etc. - I know at
> least Mike Giddens has succeeded in doing this), ways of indicating
> how we got lat and long from old records (e.g.
> georefererenceSources), or methods to define larger scale Locations
> that aren't points (e.g. footprintWKT). I think it is safe to say
> that in the future (if not now already), many or most Events
> associated with Occurrences will have an associated button click (on
> a GPS receiver, camera phone, or GPS enabled camera) that will
> automatically generate dwc:eventDate, dwc:decimalLatitude,
> dwc:decimalLongitude (with geodeticDatum=WGS84) and maybe
> coordinateUncertaintyInMeters. Thus designing a system that
> requires that these time/space snapshots be grouped together into
> artificial "Locations" is really counterproductive when those data
> are now generated and can be associated with Occurrences
> automatically. I don't know if Greg Riccardi of Morphbank is
> following this thread or not. If so he may want to comment on this
> issue based on practical experience at Morphbank. When the
> Morphbank system was set up, it required the creation of a separate
> Location record which was assigned a unique Morphbank identifier.
> Specimens were then linked to this Location. What ended up
> happening was that each Specimen having GPS metadata ended up being
> assigned to its own separate Location even if it was 20 meters from
> another specimen. In effect, each Occurrence record ended up having
> its own decimalLatitude/decimalLongitude record anyway. So the
> system ended up being more complicated than necessary.
> As I said, I agree in principle with the left side of Rich's
> diagram. Taking the practical considerations I just mentioned into
> account, I would simplify the diagram as
> Superficially, it looks more complicated, but I've gotten rid of
> several "one to many" relationships and enthroned Occurrence at its
> accustomed place in the center of the universe (or at least the
> center of the left side of the diagram). I don't have any
> philosophical objections to people structuring their data according
> to Rich's original diagram and the existing Darwin Core terms
> certainly make it possible to do so (well except for the Individual
> thing). However, I submit that many people will find it simpler
> (and easier to use tools like Darwin Core Archives) if they use the
> flatter structure that I have in the revised diagram.
> I will save my questions about the right side of Rich's diagram for
> Richard Pyle wrote:
>> I'm in Stockholm, and right now it's 10am in Hawaii, and I've
>> been awake since 7pm Hawaii time -- so my brain is a bit mush. But
>> I'll take
>> a chance and comment anyway.
>>> I will leave up to the taxonomy people the
>>> different things would be connected to the
>>> species concept and how all of their lines
>>> would be connected.
>> In my mind the "fully-normalised" (sensu Döring) relationship graph
>> something like this (notation is [One]--<[Many]; [One]--[One]) (Be
>> sure to
>> view as a fixed-width font, like Courier):
>> | |
>> [eventTime] [dateIdentified]
>> I'm following what I *think* Steve defined for [Individual], which
>> is that
>> it can be either a single individual organism or a defined set of
>> (e.g., up to at least a population).
>> So, an Occurrence is the intersection of an Individual and an
>> Event. An
>> Event is a Location+Time[+other metadata]. Each Event may have
>> Occurrences (i.e., one for each distinct Individual at the same
>> Location+Time). Also, an Individual may have multiple Occurrences
>> (one for
>> each Event at which the same Individual was documented).
>> An Individual may have multiple Identifcations. I make no
>> between "Identification" and "Determination" (nor do I make a
>> between the first identification and subsequent identifications). I
>> slightly prefer "Identification", because "Determination" seems to
>> that there is a correct answer, whereas "Identification" (to me,
>> implies an opinion. Steve, I didn't quite follow how you were
>> distinguishing these two terms -- so if you have a clear reason for
>> distinguishing them, I'd like to understand it better.
>> A single Identification should, in my mind, always join a single
>> with a single "TaxonNameUsage" instance. I'm not 100% sure how
>> TaxonNameUsage maps in DwC. I *think* it's an instance of a
>> dwc:Taxon, as
>> most of the core attributes of a TNU (acceptedNameUsage[ID],
>> parentNameUsage[ID], originalNameUsage[ID], scientificName,
>> taxonRank) are
>> represented as terms in the Taxon Class. But I'm a little fuzzy on
>> a "taxonID" maps directly to a TNUID, or if a TNUID more correcly
>> maps to
>>> The determination would have any of the properties that are
>>> terms listed in the dwc:Identification class (identifiedBy,
>>> dateIdentified, identificationReferences, identification Remarks,
>>> identificationQualifier, and typeStatus). Some properties like
>>> dateIdentified and identificationReferences would be string
>>> literals and others (especially identifiedBy) should probably
>>> be GUIDs but could be literals if they had to be.
>> I agree with what Steve wrote above. However, I'm uncomfortable with
>> Markus' suggestion of treating dwc:nameAccordingTo as a property of
>> Indentification -- even as a shortcut. I think this is a bit
>> dangerous. If
>> there is no TaxonID instance (aka "TaxonNameUsage" in my diagram
>> available to link the Identification to, then I would suggest using
>> identificationReferences as the shortcut. But that would still
>> force you to
>> attached scientificName directly to the Identification instance,
>> which I
>> think is also unwise. I'd rather the Best Practice be to
>> "manufacture" a
>> place-holder dwc:Taxon instance (if a proper one doesn't already
>> exist in
>> the content source), and apply the scientificName property to that
>> instance, rather than directly to an Identification. I know it's
>> short-hand to attach the scientificName directly to the Occurrence
>> but I actually feel less uneasy about that, because it is much more
>> obviously a shortcut. But if you're going to the trouble to
>> provide an
>> instantiated "Identification", then you ought to anchor it to a Taxon
>> instance (manufactured or real).
>> But, I guess as Greg said in his post, it may not really matter, as
>> in the
>> long run, we'll probably be able to make inferences about the proper
>> Individual<-->TaxonConcept mapping, even when it's not explicitly
>>> 1. The original label identifies the species as Juncus
>>> diffusissimus. However, there is no indicator as to who
>>> originally identified it or when. My assumption is that
>>> it was the collector (Glen N. Montz) but I don't really
>>> know that. Do I assume that, or list the original
>>> determiner as "unknown"?
>> I would make no assumptions about who was the identifiedBy person.
>> in these cases I handle these cases by either going with
>> "Unspecified", or,
>> in some cases (when I have confidence), something like "Bishop
>> Museum Staff
>> Member". Often I can deduce the identifier with some degree of
>> but usually I don't have the time to do this. The dateIdentified
>> can either
>> not be provided, or set as some range (e.g., at the very worst, on
>> or after
>> the eventDate/eventTime, and before today).
>> This is why I think that identification tags ("annotations" sensu
>> can be "documentation sources for TNUs.
>> In the web example given by Steve, we have an idetification as
>> Juncus diffusissimus Buckl.
>> Determined by: L. Urbatsch
>> Determination date: 2009
>> Completely independantly of the specimen itself, we can infer from
>> the tag
>> - Sometime between 1 Jan 2009 and 31 Dec 2009, L. Urbatsch regarded
>> genus "Juncus" as valid.
>> - Sometime between 1 Jan 2009 and 31 Dec 2009, L. Urbatsch regarded
>> species epithet "diffusissimus" [of Buckl.] as a valid species,
>> within the genus "Juncus".
>> Thus, we have at least two implied TNUs from this identification,
>> which was
>> documented on a piece of paper that happens to be fixed to LSU-BR
>> The Identification instance would link the Individual (manifest as a
>> specimen, in this case) to the TNU of "[Juncus] diffusissimus
>> Buckl. sec L.
>> Urbatsch 2009". The nameAccordingTo would be "L. Urbatsch 2009".
>> This may
>> seem redundant to have "L. Urbatsch 2009" in both the nameAccordingTo
>> attribute of thr Taxon instance, and in the identifiedBy &
>> attributes of the Identification instance -- but the fact remains
>> they are
>> fundamentally different pieces of information. One establishes an
>> of an (implied) taxon concept, and the other establishes the
>> placement of
>> LSU-BR 39823 within that taxon concept circumscription.
>> Eventually, a third party may be able to deduce (perhaps through a
>> suite of
>> other, external information) a RelationshipAssertion that maps the
>> "[Juncus] diffusissimus Buckl. sec L. Urbatsch 2009" to some other,
>> published and well-defined taxon concept (of the same or different
>> Also, if there are 100 specimens in the collection that L. Urbatsch
>> identified as "Juncus diffusissimus Buckl." in 2009, then anchoring
>> all 100
>> Identification instances to the one TNU, allows all of those
>> specimens to
>> inherit the mapping of the one "[Juncus] diffusissimus Buckl. sec L.
>> Urbatsch 2009" TNU instance to some other better-defined taxon
>> I know this is a lot of stuff to keep in one's head at the same
>> time -- but
>> as cumbersome as it seems, I am conviced it can be packacged into a
>> relatively straightforward and intuitive user UI, and modelling it
>> this way
>> improves the utility of the data (maybe dramatically) in the long
>>> 2. Do we draw a distinction between the initial identification and
>> subsequent annotations?
>>> I think the answer should be "no" and that's why I refer to both
>> generically as "determinations".
>> I agree.
>>> 3. There is really no indication given on the annotation
>>> labels as to many of the things that we would like to know,
>>> such as the concept they had in mind, any source they used (if any),
>>> or the reason why they did the annotation. So how does one
>>> connect the name that they applied to the determination when
>>> there is no indication of the concept?
>> As I said in an earlier post, the single most important way to reduce
>> taxonomic ambiguity is to try to capture (or confidently deduce)
>> the source
>> (=mapping to taxon concept). But if it can't be done, then it
>> can't be done
>> -- so I'm inclined to establish a "place-holder" dwc:Taxon
>> instance, with no
>> nameAccordingTo, and no other metadata besides the scientificName.
>>> Is this just something we can't do for old annotations
>>> and just something that we try to do from this point forward?
>>> 4. The last question is one that I really want to some
>>> opinions about. It seems to me that there are a number
>>> of reasons why one would apply a determination.
>> Hmmm....I don't think this is really useful information. I don't
>> undersatand how you would use this information ina machine-
>> processing sort
>> of way. An Identification is an Identification. In some cases, the
>> Identifier may not even be aware of the previous identification,
>> and so we
>> can necessarily infer there was a particular "reason". And even if
>> there is
>> a reason, how doe we use that information? What if there is more
>> than one
>> reason (i.e., if we are restricted to a controlled vocabulary)?
>> As far as I'm concerned, the Identifications should stand as they
>> are. If
>> needed people can annotate the Identification instances; but I
>> don't see the
>> value in machine-processing these things.
>>> Finally, a single determiner might apply
>>> several determinations to one individual and indicate
>>> in each determination the concept intended (i.e. if
>>> you subscribe to Cronquist, you'd call it X; if you
>>> like Radford's book, you'd call it Y; if you like
>>> Weakley's treatment, you'd call it Z).
>> YIKES! I don't like the idea of loading all that information on an
>> Identification instance. If the person wants to make this sort of
>> assertion, then they should establish the appropriate
>> instances among the various taxonConcepts cited.
>> Damn. Now my head is really tired. And so is the rest of me....
>> Aloha, and g'night..
> Steven J. Baskauf, Ph.D., Senior Lecturer
> Vanderbilt University Dept. of Biological Sciences
> postal mail address:
> VU Station B 351634
> Nashville, TN 37235-1634, U.S.A.
> delivery address:
> 2125 Stevenson Center
> 1161 21st Ave., S.
> Nashville, TN 37235
> office: 2128 Stevenson Center
> phone: (615) 343-4582, fax: (615) 343-6707
Arlin Stoltzfus (arlin at umd.edu)
Fellow, IBBR; Adj. Assoc. Prof., UMCP; Research Biologist, NIST
IBBR, 9600 Gudelsky Drive, Rockville, MD
tel: 240 314 6208; web: www.molevol.org
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