[tdwg-tag] DwC change review: geo terms

Wed Sep 7 01:10:46 CEST 2011

Excellent. We are in good company then in trying to resolve this issue.

On Tue, Sep 6, 2011 at 4:08 PM, Hilmar Lapp <hlapp at nescent.org> wrote:
> Where is adopting these terms now going to put us with respect to OGC
> standards, which, I think, will ultimately be more authoritative than an
> informal W3C vocabulary.
>
> I don't have enough insight into OGC standards for vocabularies for
> describing geolocations, but I have also learned earlier this year from Flip
> Dibner (copied here) that there are efforts underway within OGC to create
> RDF vocabularies (presumably corresponding to OGC's XML standards?).
>
>        -hilmar
>
> On Sep 6, 2011, at 6:33 PM, Javier de la Torre wrote:
>
>> Hi John,
>>
>> As you mention from previous discussion I would still adopt option number
>> 1 as I believe there is enough tools out there to handle transformations.
>> The current situation I think is much worst on the consumer part and I think
>> is time to think more on data use than on data mobilization.
>>
>> Best,
>>
>> Javier.
>>
>> On 07/09/2011, at 00:00, John Wieczorek <tuco at berkeley.edu> wrote:
>>
>>> Perhaps my message was too long for easy digestion and action, as I've
>>> received no responses. I will take the initiative to initiate option
>>> 3. No further action from the TAG on this at this point. Be prepared
>>> though, VOTES by the TAG on publicly resolved issues are forthcoming
>>> very soon.
>>>
>>> On Sat, Sep 3, 2011 at 9:34 AM, John Wieczorek <tuco at berkeley.edu> wrote:
>>>>
>>>> Hi TAGers,
>>>>
>>>> I am deep in the review process for the proposed changes to Darwin
>>>> Core, trying to do due diligence. Some of the change requests are
>>>> challenging to summarize to determine if there is consensus, in spite
>>>> of, or because of the discussions. One of the requests on which I’d
>>>> like some TAG help before proposing a solution is the request for the
>>>> inclusion of the terms from the geo: namespace
>>>> (xmlns:geo="http://www.w3.org/2003/01/geo/wgs84_pos#").
>>>>
>>>> Support in tdwg-content for this request comes from multiple
>>>> independent sources. There has been a long history of discussion
>>>> (http://lists.tdwg.org/pipermail/tdwg-tag/2010-August/000050.html),
>>>> beginning in anticipation of the 2010 TDWG BioBlitz. The proposal has
>>>> gone through the minimum 30-day public review and discussion on the
>>>> forum tdwg-content at lists.tdwg.org:
>>>>
>>>> http://lists.tdwg.org/pipermail/tdwg-content/2011-July/002581.html
>>>>
>>>> There seems to be general support for the additions, however, after
>>>> reviewing the discussions and the references. I have the following
>>>> observations/concerns:
>>>>
>>>> 1) The discussions presented geo:lat and geo:lng as W3C standards.
>>>> This is not actually the case. These terms were created by the W3C
>>>> Semantic Web Interest Group in 2003. The documentation for these terms
>>>> (http://www.w3.org/2003/01/geo/) states:
>>>>
>>>> "This document was created as an informal collaboration within W3C's
>>>> Semantic Web Interest Group. This work is not currently on the W3C
>>>> recommendation track for standardization, and has not been subject to
>>>> the associated review process, quality assurance, etc. If there is
>>>> interest amongst the W3C membership in standards work on a
>>>> location/mapping RDF vocabulary, this current work may inform any more
>>>> formal efforts to follow."
>>>>
>>>> These terms do seem to have widespread usage in the semantic web.
>>>> Should we be concerned that they are not part of a standard?
>>>>
>>>> 2) geo:lat and geo:lng are not semantically equivalent to the existing
>>>> Darwin Core terms decimalLatitude and decimalLongitude, which have
>>>> been a part of the Darwin Core since it 2003 (or before, if we ignore
>>>> the missing Datum term in earlier versions). The addition of the geo:
>>>> terms as a third set of geolocation terms for Darwin Core raised
>>>> concerns about confusion. I share this concern. An option would be to
>>>> adopt these terms and deprecate dwc:decimalLatitude, dwc:Longitude,
>>>> and dwc:geodeticDatum. Data that would have occupied these terms would
>>>> go instead to dwc:verbatimLatitude dwc:verbatimLongitude, and
>>>> dwc:verbatimSRS. I see a couple of problems with this. First, most of
>>>> the time the data in the decimal coordinate fields are not the
>>>> verbatim originals, so this would be a misuse of the Darwin Core
>>>> terms. Second, this change would make it more difficult for data
>>>> consumer’s to use existing georeferences. Here’s how. Right now the
>>>> verbatim fields are meant to hold the original coordinate information,
>>>> which means they have a wide variety of content - everything from UTMs
>>>> to custom-encoded coordinates, in any conceivable format. Meanwhile,
>>>> the data in the decimal coordinates fields can be much more readily
>>>> transformed into the desired standardized spatial reference system
>>>> afforded by the geo: terms, because the values are at least
>>>> standardized on decimal degrees and only a datum transformation has to
>>>> be done on them.
>>>>
>>>> Do we abandon the dwc: terms decimalLatitude, decimalLongitude, and
>>>> geodeticDatum? Do we abandon them now? Do we build the simplest
>>>> possible tools necessary for anyone to do the transformations so that
>>>> these terms are no longer needed? If so, do we wait until those tools
>>>> exist?
>>>>
>>>> 3) Additional concern was expressed that the term geo:alt should also
>>>> be added. No one has made a formal request for this. However, if the
>>>> other geo: terms were adopted, it might be silly not to adopt this one
>>>> as well. Doing so would raise a host of issues similar to those raised
>>>> for lat and lng.
>>>>
>>>> I don’t have a good solution. The best short-term one, in my opinion,
>>>> is to leave Darwin Core as it is, and to recommend that if
>>>> applications (or aggregators) want to share “cleansed” point-based
>>>> georeferences, that they do so with the geo: tags, the values for
>>>> which they derive through transformations to WGS84 of the DwC decimal
>>>> coordinates and geodeticDatum.
>>>>
>>>> Options:
>>>>
>>>> 1) Accept the proposal, adding geo:lat, geo:lng, and geo:alt to the
>>>> list of recommended terms for DwC.
>>>>
>>>> 2) Reject the proposal pending further directed research into a
>>>> comprehensive solution that considers all geospatial terms in Darwin
>>>> Core (including footprintWKT, for example).
>>>>
>>>> 3) Reject the proposal for now, reopening the public discussion with
>>>> these concerns.
>>>>
>>>> Others?
>>>>
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>
> --
> ===========================================================
> : Hilmar Lapp  -:- Durham, NC -:- informatics.nescent.org :
> ===========================================================
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