Re: ISA Core Location Vocabulary

Hello Ghislain,

Thank you for sharing this. It is an impressive undertaking, I do hope 
you will let us know when it is finished.

Do you plan to include links to the OGC CRS URIs in your CRS 
vocabularies? As far as I know, those URIs do not resolve to RDF (yet), 
but they can be expected to be widely used identifiers of CRSes.

About your remark about allowing a geometry to have different CRSes: Do 
you mean that you see a geometry as a real world phenomenon that can 
have multiple data encodings? That would be different from the OGC/ISO 
definition of what a geometry is.

Regards,
Frans

On 2013-12-20 15:07, Ghislain Atemezing wrote:
> Hi Frans,
>> A completely different thing: I see that the Location Core Vocabulary
>> does not define a new way of encoding geometry, but rather permits the
>> encoding specified in GeoSPARQL and Basic Geo. Was NeoGeo ever
>> considered too? One consideration may be that the world at large will
>> not be helped by having many different encodings for geometry. I think I
>> would prefer just an encoding of WKT, but without including the (URI of)
>> the coordinate reference system (CRS). I believe the SRS should be a
>> separate entity, to be applicable to a geometry, to a collection of
>> geometries, or to a dataset.
> +1. This is definitively a way to go and with the colleagues at 
> IGN-France, we are finishing two vocabularies that basically reuse 
> NeoGeo, GeoSPARQL to re-define the existing semantics of POINT by 
> taking into account what you just pointed out..
>
> 1- A vocab for CRS: http://goo.gl/UchRcy, that will be tied to the 
> publication of at least the list of CRS maintained at IGN.
> 2- A yet another vocab for geometry, where we allow to have different 
> CRS for a geometry. See http://goo.gl/nsJfei.
>
> You can play with this application, "Perfect School"[1] where from the 
> initial dataset in LAMBERT93, we provide for each resource two 
> different encoded values for the geometries.
>
> For example, we have queries like this
>
> [ ?s rdf:type aiiso:School ;
>         geom:geometry ?loc ;
>         ecole:nature ?nature .
>
>     ?loc geom:coordX  ?lat ;
>         geom:coordY ?lng ;
>         geom:systCoord  ignfr:wgs84g . # here we specify the CRS, e.g: 
> ignfr:ntflamb2e
> ]
>
> where we will publish all the CRS in this domain space ignfr: 
> <http://data.ign.fr/id/ignf/systemecoordonnees/>
>
> More to come when all the current issues are solved and the vocabs are 
> in a stable version...
>
> Happy Holidays to everyone.
>
> [1]  http://semantics.eurecom.fr/datalift/PerfectSchool/
>

Received on Monday, 23 December 2013 11:10:50 UTC