good questions Jean-Marc, I will organize a session early in the new year to address some of them. In your case geo:lat and geo:long are not part of OGC GeoSPARQL but require a transformation. We have a tool in place for that in Jena. And yes displaying large datasets need dedicated strategies for efficient processing. The points raised by you would make a good problem statement for our session next year. Not sure if you have attended the ApachCon 2020 GeoSPARQL session last month but it's where I mentioned further collaboration with third party tool developers as a possibility. stay tuned.
Marco On Mon, Oct 26, 2020 at 9:14 AM Jean-Marc Vanel <jeanmarc.va...@gmail.com> wrote: > After reading the official > https://jena.apache.org/documentation/geosparql/ > I'm puzzled as to concrete how to . > > My simple export use case > > - I have a TDB 1 database with geo:lat and long properties; the Jena > geosparql dependency is added to my application > - I have a LeafLet viewer able to display any RDF document with geo:lat > and long properties ; example map > < > https://semantic-forms.cc:1953/assets/geo-map/geo-map.html?link-prefix=http://semantic-forms.cc:1953/display?displayuri=&lang=fr&url=https://semantic-forms.cc:1953/sparql?query=%0APREFIX+form%3A+%3Chttp%3A%2F%2Fraw.githubusercontent.com%2Fjmvanel%2Fsemantic_forms%2Fmaster%2Fvocabulary%2Fforms.owl.ttl%23%3E+%0APREFIX+rdfs%3A+%3Chttp%3A%2F%2Fwww.w3.org%2F2000%2F01%2Frdf-schema%23%3E+%0APREFIX+geo%3A+%3Chttp%3A%2F%2Fwww.w3.org%2F2003%2F01%2Fgeo%2Fwgs84_pos%23%3E+%0APREFIX+foaf%3A+%3Chttp%3A%2F%2Fxmlns.com%2Ffoaf%2F0.1%2F%3E+%0A%0ACONSTRUCT+%7B%0A++%3Fthing+geo%3Along+%3FLONG+.%0A++%3Fthing+geo%3Alat+%3FLAT+.%0A++%3Fthing+rdfs%3Alabel+%3FLAB+.%0A++%3Fthing+foaf%3Adepiction+%3FIMG+.%0A%7D+WHERE+%7B%0A++graph+%3Fg+%7B%0A++++%3Fthing+%3Chttp%3A%2F%2Fpurl.org%2FNET%2Fc4dm%2Fevent.owl%23produced_in%3E+%3Chttp%3A%2F%2Fsemantic-forms.cc%3A1952%2Fldp%2FCormoz%3E+.%0A++%7D%0A++graph+%3Fgcoord+%7B%0A++++%3Fthing+geo%3Along+%3FLONG+.%0A++++%3Fthing+geo%3Alat+%3FLAT+.%0A++%7D%0A++OPTIONAL+%7B%0A+++graph+%3Fg1+%7B%0A++++%3Fthing+rdfs%3Alabel+%3FLAB+%7D+%7D%0A++OPTIONAL+%7B%0A+++graph+%3Fg2+%7B%0A++++%3Fthing+%3Curn%3AdisplayLabel%3E+%3FLAB+%7D+%7D%0A%0A++OPTIONAL+%7B%0A+++graph+%3Fg3+%7B%0A++++%3Fthing+foaf%3Adepiction+%3FIMG+%7D+%7D%0A++OPTIONAL+%7B%0A+++graph+%3Fg4+%7B%0A++++%3Fthing+foaf%3Aimg+%3FIMG+%7D+%7D%0A%0A++++OPTIONAL+%7B%0A+++graph+%3FgrCount+%7B%0A++++%3Fthing+form%3AlinksCount+%3FCOUNT.%0A++%7D+%7D%0A%7D%0AORDER+BY+DESC%28%3FCOUNT%29%0A > > > ; but I found that JavaScript based displayers are falling on their > knees > (becoming very slow) for thousands of points > - so I plan to use QGIS, so I need an export from RDF to one of the > formats QGIS supports: GML, GeoJSON , etc > > How can I do that ? > Do I have to use one of the convert* methods in > > https://jena.apache.org/documentation/javadoc/geosparql/index.html?org/apache/jena/geosparql/configuration/GeoSPARQLOperations.html > ? > > Jean-Marc Vanel > < > http://semantic-forms.cc:1952/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me > > > +33 (0)6 89 16 29 52 > Twitter: @jmvanel , @jmvanel_fr ; chat: irc://irc.freenode.net#eulergui > Chroniques jardin > < > http://semantic-forms.cc:1952/history?uri=http%3A%2F%2Fdbpedia.org%2Fresource%2FChronicle > > > -- --- Marco Neumann KONA
