Hi Greg The data are available at this SPARQL endpoint : http://semantic-forms.cc:1952/sparql2 the queries are given in this thread.
BUT, I reread the documentation, and added org.apache.jena.geosparql.configuration.GeoSPARQLConfig.setupMemoryIndex() before calling TDBFactory.createDataset() And now , with the same very simple query with spatial:withinBox() , it says : org.apache.jena.sparql.expr.ExprEvalException: Dataset Context does not contain SpatialIndex. >From the documentation, it is not clear what is the minimal, or optimal, configuration. A casual reading even gives the impression that no configuration is necessary. Jean-Marc Vanel <http://semantic-forms.cc:9112/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me> +33 (0)6 89 16 29 52 Le mer. 28 oct. 2020 à 23:29, Greg <galbis...@mail.com> a écrit : > Hi Jean-Marc, > > If you have an sample of data then I can take a look into this further. > > Thanks, > > Greg > > On 26/10/2020 16:56, Jean-Marc Vanel wrote: > > Indeed this helps, but it's still not clear weather and how I have to > > prepare the database for GeoSparlql queries. > > > > I changed my query according to Greg's advice: > > PREFIX spatial: <http://jena.apache.org/spatial#> > > SELECT * WHERE { > > ?feature spatial:withinBox( 43.0 0.0 48.0 10.0 100 ) > > } LIMIT 100 > > but no results. > > Of course I checked that I have many triples with geo: coordinates within > > that rectangle : > > PREFIX geo: <http://www.w3.org/2003/01/geo/wgs84_pos#> > > SELECT * WHERE { > > ?S geo:lat ?LAT . > > ?S geo:long ?LON . > > } LIMIT 100 > > > > Regarding simple export from triples with geo: coordinates to GML or > > GeoJson, I'll write some code that I'll share. > > > > Jean-Marc Vanel > > < > http://semantic-forms.cc:9112/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me > > > > +33 > > (0)6 89 16 29 52 > > > > > > Le lun. 26 oct. 2020 à 16:38, Greg Albiston <galbis...@mail.com> a > écrit : > > > >> Hi Jena-Marc, > >> > >> The namespace <http://geovocab.org/spatial#> is for NeoGeo Spatial > >> ontology, which has similarities to GeoSPARQL specification but is not > >> fully compliant. > >> > >> The Apache Jena spatial property functions use > >> <http://jena.apache.org/spatial#>. These are additional functions that > >> extend the GeoSPARQL standard. > >> > >> So you are likely getting no result as the "spatial:withinBox" function > >> in the query is undefined. > >> > >> Regarding your other question about GML and GeoJSON documents. The > >> GeoSPARQL standard doesn't cover serialisation from or to geospatial > >> document formats into the GeoSPARQL "Feature/Geometry/GeometryLiteral" > >> structure. This is likely because it is expected that most use cases > >> would stay in RDF format once setup. From my experience the GML > >> standards are also unbelievably convoluted to fully support. > >> > >> It may be straight forward to convert a list of points to a minimum GML > >> document that QGIS accepts. > >> > >> The "convert" functions are to harmonise a dataset to a single SRS and > >> datatype to reduce overhead and confusion from switching between > >> different formats when querying the data. Or to switch a dataset from > >> one SRS or datatype to another, i.e. consolidating diverse data sources. > >> They aren't for generating non-RDF spatial documents. These are also for > >> GeoSPARQL structure datasets so a dataset using the LatLon geo > >> predicates would need to be converted (for which the > >> "convertGeoPredicates" might be useful). > >> > >> Hope this helps, > >> > >> Greg > >> > >> > >> On 26/10/2020 14:17, Jean-Marc Vanel wrote: > >>> I missed ApacheCon, and I need some concrete hints sooner than next > year. > >>> > >>> Currently my database gives an empty answer to : > >>> PREFIX spatial: <http://geovocab.org/spatial#> > >>> # ?feature spatial:withinBox(?latMin ?lonMin ?latMax ?lonMax [ ?limit]) > >>> SELECT * WHERE { > >>> ?feature spatial:withinBox( 43.0 0.0 46.0 10.0 100 ) > >>> } LIMIT 100 > >>> > >>> Should I apply once for all GeoSPARQLOperations.convert() ? > >>> static Dataset > >>> < > >> > https://jena.apache.org/documentation/javadoc/arq/org/apache/jena/query/Dataset.html?is-external=true > >>> convert > >>> < > >> > https://jena.apache.org/documentation/javadoc/geosparql/org/apache/jena/geosparql/configuration/GeoSPARQLOperations.html#convert-org.apache.jena.query.Dataset- > >>> (Dataset > >>> < > >> > https://jena.apache.org/documentation/javadoc/arq/org/apache/jena/query/Dataset.html?is-external=true > >>> dataset) > >>> Convert the input dataset to the most frequent coordinate reference > >> system > >>> and default datatype. > >>> > >>> Jean-Marc Vanel > >>> < > >> > http://semantic-forms.cc:9112/display?displayuri=http://jmvanel.free.fr/jmv.rdf%23me > >>> +33 > >>> (0)6 89 16 29 52 > >>> > >>> > >>> Le lun. 26 oct. 2020 à 11:02, Marco Neumann <marco.neum...@gmail.com> > a > >>> écrit : > >>> > >>>> 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 > >>>> > >
