- From: Kostis Kyzirakos <Kostis.Kyzirakos@cwi.nl>
- Date: Mon, 6 Jan 2014 19:14:56 +0100
- To: Raphaƫl Troncy <raphael.troncy@eurecom.fr>
- Cc: "Frans Knibbe | Geodan" <frans.knibbe@geodan.nl>, LocAdd W3C CG Public Mailing list <public-locadd@w3.org>
- Message-ID: <CAJUi=VFswJwL3_0aOjpC1S3bYvQ5Q2vWRDPp7sDOK3nVSK1j8w@mail.gmail.com>
Hi, GeoSPARQL took most of the functions that check or return properties of >> a geometry (all but SRID if I am not mistaken) and defined properties >> with the >> same name (e.g., the properties geo:isEmpty, geo:isSimple) so that one >> would >> be able to assert whether a geometry is empty etc. This is defined at the >> Geometry Extension component of GeoSPARQL. >> > > Yes, correct. Could you please provide the link to the owl file (if it > exists) where the Geometry Extension component of GeoSPARQL (vocabulary) is > defined? And can you confirm that this vocabulary does not yet contain a > specific property that could be used to indicate the CRS used in a > particular geometry? The complete set of files can be found here: http://schemas.opengis.net/geosparql/geosparql-1_0_1.zip GeoSPARQL follows a modular architecture and some extensions can be parameterized according to several parameters (e.g., WKT or GML serialization standards). The files ./gml/3.2.1/gml_32_geometries.rdf and ./sf/1.0/simple_features_geometries.rdf provide information about the respective serialization standards, and ./geosparql/1.0.1/geosparql_vocab_all.rdf contains the complete GeoSPARQL vocabulary. The definition of the classes geo:SpatialObject and geo:Feature is defined at the Core extension. The Geometry extension defines the class geo:Geometry, the properties: geo:hasGeometry, geo:hasDefaultGeometry, geo:dimension, geo:spatialDimension, geo:coordinateDimension, geo:isEmpty, geo:isSimple, geo:hasSerialization, geo:asWKT, geo:asGML and the datatypes geo:wktLiteral and geo:gmlLiteral. This extension defines some function (boundary, envelope, union, convexHull, distance) that is not relevant to our discussion. The Topology Vocabulary Extension defines a set of properties (geo:sfContains, geo:sfCrosses, geo:sfEquals etc.) with domain and range a geo:SpatialObject that allows the user to assert that a specific topological relationship holds between two spatial objects. This vocabulary is intended to be used by reasoners and could be used in the context of the locn vocabulary in order to allow users to define for example neighboring locations. The Geometry topology extension defines a set of SPARQL extension functions like sfEquals, sfContaines etc. Cheers, Kostis
Received on Monday, 6 January 2014 18:15:51 UTC