Intersection of geometries as GeoSPARQL result

Question

I'm querying two geosparql conform datasets at endpoint http://onto.fel.cvut.cz:7200/sparql trying to get intersectred geometry as result using GeoSPARQL language.

PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#>
PREFIX geo: <http://www.opengis.net/ont/geosparql#>
PREFIX geof: <http://www.opengis.net/def/function/geosparql/>
PREFIX databaseTableFVU: <http://onto.fel.cvut.cz/ontologies/town-plan/databaseTableFVU/>
PREFIX databaseTableSSVU: <http://onto.fel.cvut.cz/ontologies/town-plan/databaseTableSSVU/>
PREFIX geosparql: <http://www.opengis.net/ont/geosparql#>
PREFIX common: <http://onto.fel.cvut.cz/ontologies/town-plan/common/>
PREFIX xsd: <http://www.w3.org/2001/XMLSchema#>
SELECT distinct ?var1 ?var2
WHERE  {
       {
        ?var1 databaseTableFVU:kodfp1_a ?val1.
        ?var1 geosparql:hasGeometry ?geometry1.
        ?geometry1 geosparql:asWKT ?WKT1.
        FILTER(?val1 = "OB" || ?val1 = "OV")
       }
       {
        ?var2 databaseTableSSVU:kod ?val2.
        ?var2 geosparql:hasGeometry ?geometry2.
        ?geometry2 geosparql:asWKT ?WKT2.
        FILTER(?val2 != "BD" && ?val2 != "BQ" && ?val2 != "BRV" && ?val2 != "BRR")
      }
FILTER(geof:sfIntersects(?WKT1, ?WKT2)).
}

I know that this query returns only features, that intersects, but I have no idea how to actually get intersection as geometry representation.

Answer 1

It is actually not possible with GeoSPARQL.

GeoSPARQL is using java functions that are called by

PREFIX geof: <http://www.opengis.net/def/function/geosparql/>

What I recommend is the creation of your own java function, which can be tremendous if you are not familiar with it.