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Re: Fwd: Reviewing the GeoSPARQL document?

From: Carlos Buil Aranda <cbuil@fi.upm.es>
Date: Tue, 19 Apr 2011 16:58:35 +0200
Message-ID: <4DADA31B.5050205@fi.upm.es>
To: ivan@ivan-herman.net
CC: SPARQL Working Group <public-rdf-dawg@w3.org>


Dear Ivan,

please, find below the comments I sent to the mailing list a bit ago 
regarding the GeoSPARQL specification.

Carlos

Dear all, here come my comments about the GeoSPARQL specification.

There is a typo in item 1.2.4.3 which described LineString class, there 
is the name Curve instead of LineString in the URI identifying the resource

In the SimpleFeature object from OGC we came up with the following 
questions: to what is referring the ArcString class, is the same class 
than SimpleFeature in OGC? Wht there is no class LinearRing in the 
model? Why compose relations such TIN which is composed by triangles or 
MultiPoint are not taken into account? Why envelope and boundary 
attributes are taken into account as filter function and not as class 
properties?

Some more comments about what it was discussed in GeoVocamp a month ago. 
There people say that geoSPARQL defines geometry using a literal (with 
GML or WKT) but people in GeoVoCamp think that is is important to make 
geometry explicit in RDF allowing access to different representations 
via content negotation (http://vocamp.org/wiki/Geometry-vocab and 
http://code.google.com/p/neogeovocab/ )

In general this model is widely used, Virtuoso and other implementations 
(like geometry2rdf) in general follow the same approach than the one 
described in the specification.

Cheers,

Carlos



On 26/02/2011 13:13, Axel Polleres wrote:
> Forwarding this with Ivan's permission... the Open Geospatial Consortium [1] asks us for a review of their GeoSPARQL specification.
> Would anybody volunteer to have a look and provide a review in the name of our group? (will put this under next week's agenda's admin issues)
>
> Axel
>
>
>>> On 16 Feb 2011, at 08:55, Ivan Herman wrote:
>>>
>>>> Lee, Axel,
>>>>
>>>> we have recently received a copy of the Draft Candidate Standard of the Open Geospatial Consortium[1] called GeoSPARQL. I have put a copy of the document on our site[2]. OGC would like us (where 'us' means the W3C SPARQL community in their words) to have a look at the document and give them our comments.
>>>>
>>>> A *very* cursory look at the document reveals that the document defines a general vocabulary, including datatypes, for GeoSpatial information (that may not be relevant for the SPARQL group only), but they also define a set of domain specific SPARQL filter functions as well as what they call 'query transformation rules'.
>>>>
>>>> The filter functions should be looked into in any case, and be compared with the current work of the WG on defining filter functions (eg, if there are overlaps, the way they are defined, etc).
>>>>
>>>> The transformation seems to be some sort of a 'macro' like facility to change a simple query pattern into something more complex, ie, Query Pattern ->  Query Pattern transformations defined via RIF rules. (Sandro, would it be necessary/useful to have somebody from the RIF community look at this, too? If so, who?)
>>>>
>>>> They are obviously interested in our technical comments. But, I believe, we should also make it sure that whatever ogc does in this area does not violate SPARQL 1.1; even better, some of their features might become easier with SPARQL 1.1, and that might be useful for them to know.
>>>>
>>>> So, here comes of course the tough issue: do you think you could find somebody (singular or, better, plural) in the SPARQL WG who could look at this document? I would expect this to be interesting for vendors because, after all, services might provide these functionalities as an extra feature...
>>>>
>>>> Thanks a lot!
>>>>
>>>> Ivan
>>>>
>>>>
>>>> [1] http://www.opengeospatial.org/
>>>> [2] http://www.w3.org/2011/02/GeoSPARQL.pdf
>>>>
>>>> ----
>>>> Ivan Herman, W3C Semantic Web Activity Lead
>>>> Home: http://www.w3.org/People/Ivan/
>>>> mobile: +31-641044153
>>>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>>>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>>>
>>>>
>>>>
>>>>
>>>>
>>
>> ----
>> Ivan Herman, W3C Semantic Web Activity Lead
>> Home: http://www.w3.org/People/Ivan/
>> mobile: +31-641044153
>> PGP Key: http://www.ivan-herman.net/pgpkey.html
>> FOAF: http://www.ivan-herman.net/foaf.rdf
>>
>>
>>
>>
>>
>
>
Received on Tuesday, 19 April 2011 14:58:57 GMT

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