- From: Oscar Corcho <ocorcho@fi.upm.es>
- Date: Sun, 22 Dec 2013 14:58:03 +0100
- To: Ghislain Atemezing <auguste.atemezing@eurecom.fr>, Frans Knibbe | Geodan <frans.knibbe@geodan.nl>
- CC: <public-locadd@w3.org>
Dear Ghis, Thanks for sharing this best practice from your side. We are currently at LocaliData [1] facing the same problem of needing to encode explicitly the coordinate system in which a geometry is provided, and we were looking for an RDF-aware knowledge base of coordinate systems that may be already available. For the time being we use just a literal like: ?x geom:crs "EPSGS23030" And we also encode the crs inside the WKT literals, but this is far from perfect. When do you plan to have this KB of coordinate systems already publicly available? We would love to be able to reuse it. Regards, Oscar [1] http://www.localidata.com/, http://datos.localidata.com/ -- Oscar Corcho Ontology Engineering Group (OEG) Departamento de Inteligencia Artificial Facultad de Informática Campus de Montegancedo s/n Boadilla del Monte-28660 Madrid, España Tel. (+34) 91 336 66 05 Fax (+34) 91 352 48 19 El 20/12/13 15:07, "Ghislain Atemezing" <auguste.atemezing@eurecom.fr> escribió: >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/ > >-- >Ghislain Atemezing >EURECOM, Multimedia Communications Department >Campus SophiaTech >450, route des Chappes, 06410 Biot, France. >e-mail: auguste.atemezing@eurecom.fr & ghislain.atemezing@gmail.com >Tel: +33 (0)4 - 9300 8178 >Fax: +33 (0)4 - 9000 8200 >Web: http://www.eurecom.fr/~atemezin >Google+:http://google.com/+GhislainATEMEZING >Twitter:@gatemezing >
Received on Sunday, 22 December 2013 13:58:41 UTC