Even though the wording is slightly ambiguous IMHO, req 11 confirms that the CRS is optional - so is this actually a bug? I may be a unworkable limitation that it can only handle the implicit default and for all other CRS data would effectively be corrupted by misrepresenting its CRS.
If clients cant handle the absence at all, it may be a best practice to include it. You probably should also try data with a different CRS in case it is omitting it just for the default case Rob A On Fri, 1 Apr 2016 at 08:50 fernando baculima <[email protected]> wrote: > Hi All. > > > I have found a Little problem in the implementation of GeoSPARQL. The > problem is that Marmotta doesn't returns the spatial reference URI before > WKT, as it is specified in the Geosparql Standard Document. Req 10 and Req > 11. [1] > > > Req 10 > All RDFS Literals of type geo:wktLiteral shall consist of an optional URI > identifying the coordinate reference system followed by > Simple Features Well Known Text (WKT) describing a geometric value. Valid > geo:wktLiterals are formed by concatenating a valid, > absolute URI as defined in [RFC 2396], one or more spaces (Unicode U+0020 > character) as a separator, and a WKT string as defined in > Simple Features [ISO 19125-1]. > > Req 11 > The URI <http://www.opengis.net/def/crs/OGC/1.3/CRS84> shall be assumed as > the spatial reference system > for geo:wktLiterals that do not specify an explicit spatial reference > system URI > > > Example: > > SPARQL Query > > PREFIX geo: <http://www.opengis.net/ont/geosparql#> > Select ?wkt > WHERE > { > ?r geo:hasGeometry ?geo. > ?geo asWKT ?geo > } > limit 1 > > > Marmotta response: > > wkt > Point(-78.562245 26554456)^^http://www.opengis.net/ont/sf#wktLiteral > > > But Marmotta should return:: > > wkt > <http://www.opengis.net/def/crs/OGC/1.3/CRS84> Point(-78.562245 > 26554456)^^ > http://www.opengis.net/ont/sf#wktLiteral > > > > > This URI is important for applications that need to identify the reference > system and show the data in a map, for example MAP4RDF (UPM).[2] and > openMapsJS (UCUENCA). [3]. > > > > [1]. http://www.opengeospatial.org/standards/geosparql > [2]. http://oeg-dev.dia.fi.upm.es/map4rdf/ > [3]. https://github.com/marcelocaj/openmapjs > > > 2016-03-23 10:15 GMT-05:00 fernando baculima <[email protected]>: > > > Hi Sergio. > > > > > > So I think it would be good to put a suggestion in the WIKI > > > > or here > > > > [http://marmotta.apache.org/kiwi/geosparql.html] > > > > to help users of geosparql > > > > > > > > Cheers > > > > 2016-03-22 12:50 GMT-05:00 Sergio Fernández <[email protected]>: > > > >> Hi Fernando, > >> > >> On Tue, Mar 22, 2016 at 6:38 PM, Fernando Baculima < > >> [email protected] > >> > wrote: > >> > > >> > I am Fernando. > >> > I followed and I have collaborated in implementing geosparql since its > >> > beginnig. > >> > > >> > >> Good to see you back. > >> > >> In the RDF, exists the following relation > >> > http://geo.marmotta.es/ontology#hasExactGeometry is subPropertyOf > >> > http://www.opengis.net/ont/geosparql#hasGeometry > >> > Then marmotta should infer this relation. > >> > > >> > > >> > To solve this problem. I implement the following rule in the reasoner > >> > Module. > >> > @prefix rdfs: <http://www.w3.org/2000/01/rdf-schema#> > >> > ($1 <http://www.w3.org/2000/01/rdf-schema#subPropertyOf> $2), ($3 $1 > >> $4) > >> > -> ($3 $2 $4) > >> > > >> > Then my question is: > >> > Is this process right for all geosparql users? > >> > Is there other way for marmotta to infer this relation? > >> > > >> > >> Yes, that's the expected behavior. The current KiWi SPARQL > implementation > >> only supports the RDF Entailment: > >> https://www.w3.org/TR/sparql11-entailment/#RDFEntRegime but not further > >> entailment such as RDFS, OWL or D-entailment. So the single way to get > >> ssuch queries working as you expected is having a reasoner program > >> materializing those inferences. > >> > >> Hope that helps. > >> > >> Cheers, > >> > > > > >
