Building Geospatial Index when working with JENA FUSEKI

Question

I would like to use the nearby geospatial function which is described as supported here through JENA FUSEKI - https://jena.apache.org/documentation/query/spatial-query.html

I need to build the geospatial Index for the query to work. The instructions are as follows (taken from above link):

---

Build the TDB dataset:

java -cp $FUSEKI_HOME/fuseki-server.jar tdb.tdbloader --tdb=assembler_file data_file

using the copy of TDB included with Fuseki. Alternatively, use one of the TDB utilities tdbloader or tdbloader2:

$JENA_HOME/bin/tdbloader --loc=directory data_file

then build the spatial index with the jena.spatialindexer:

java -cp jena-spatial.jar jena.spatialindexer --desc=assembler_file

---

Assuming I knew which file is the assembler file in my FUSEKI folder (I don't), I search for jena-spatial.jar in my latest jena download. Having found it is not there, I search for it and find a copy of the jar here - https://jar-download.com/?detail_search=g%3A%22org.apache.jena%22+AND+a%3A%22jena-spatial%22&search_type=av&a=jena-spatial&p=1

I try running it, but I get the error "Could not find or load main class jena.spatialindexer". I do searchers for jena.spatialindexer and I find a match (cannot post here as at link post limit).

At this point I am wondering would it be possible to make this just a little bit more complicated? You know, I obviously have all the time in the world to search through google trying to figure out these cryptic clues.

In short, if anyone out there has done this before, please could you point out where I am going wrong?

Kindest regards,

Kris.

Answer 1

Just in case it might help, find below my configuration

@prefix fuseki:  <http://jena.apache.org/fuseki#> .
@prefix rdf:     <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .
@prefix rdfs:    <http://www.w3.org/2000/01/rdf-schema#> .
@prefix tdb:     <http://jena.hpl.hp.com/2008/tdb#> .
@prefix ja:      <http://jena.hpl.hp.com/2005/11/Assembler#> .
@prefix :        <#> .

@prefix spatial: <http://jena.apache.org/spatial#> .


# TDB
[] ja:loadClass "org.apache.jena.tdb.TDB" .
tdb:DatasetTDB  rdfs:subClassOf  ja:RDFDataset .
tdb:GraphTDB    rdfs:subClassOf  ja:Model .

# Spatial
[] ja:loadClass "org.apache.jena.query.spatial.SpatialQuery" .
spatial:SpatialDataset  rdfs:subClassOf  ja:RDFDataset .
#spatial:SpatialIndexSolr  rdfs:subClassOf  spatial:SpatialIndex .
spatial:SpatialIndexLucene  rdfs:subClassOf   spatial:SpatialIndex .

## ---------------------------------------------------------------
## This URI must be fixed - it's used to assemble the spatial dataset.

:spatial_dataset rdf:type     spatial:SpatialDataset ;
    spatial:dataset   <#tdb_dataset_readwrite> ;
    ##spatial:index   <#indexSolr> ;
    spatial:index     <#indexLucene> ;
    .

<#tdb_dataset_readwrite> rdf:type      tdb:DatasetTDB ;
    tdb:location "/myfolder" ;
##     # Query timeout on this dataset (milliseconds)
##     ja:context [ ja:cxtName "arq:queryTimeout" ;  ja:cxtValue "1000" ] ;
##     # Default graph for query is the (read-only) union of all named graphs.
       tdb:unionDefaultGraph true ;
    .

<#indexLucene> a spatial:SpatialIndexLucene ;
    #spatial:directory <file:Lucene> ;
   ## spatial:directory "mem" ;
    spatial:directory <file:/myfolder/spatial> ;
    spatial:definition <#definition> ;
    .

<#definition> a spatial:EntityDefinition ;
    spatial:entityField      "uri" ;
    spatial:geoField     "geo" ;
    # custom geo predicates for 1) Latitude/Longitude Format
    spatial:hasSpatialPredicatePairs (
         [ spatial:latitude :latitude_1 ; spatial:longitude :longitude_1 ]
         [ spatial:latitude :latitude_2 ; spatial:longitude :longitude_2 ]
         ) ;
    # custom geo predicates for 2) Well Known Text (WKT) Literal
    spatial:hasWKTPredicates (:wkt_1 :wkt_2) ;
    # custom SpatialContextFactory for 2) Well Known Text (WKT) Literal
    spatial:spatialContextFactory
         "org.locationtech.spatial4j.context.jts.JtsSpatialContextFactory"
    .
#         "com.spatial4j.core.context.jts.JtsSpatialContextFactory"


<#service_tdb1> rdf:type fuseki:Service ;
    rdfs:label                      "TDB Service" ;
    fuseki:name                     "tdb_spatial" ;
    fuseki:serviceQuery             "query" ;
    fuseki:serviceQuery             "sparql" ;
    fuseki:serviceUpdate            "update" ;
    fuseki:serviceUpload            "upload" ;
    fuseki:serviceReadWriteGraphStore      "data" ;
    # A separate read-only graph store endpoint:
    fuseki:serviceReadGraphStore       "get" ;
    fuseki:dataset                  :spatial_dataset  ;

as you can see I have changed the class name to org.locationtech.spatial4j.context.jts.JtsSpatialContextFactory. Besides when running fuseki I have to include another jar file in the classpath as otherwise I have issues with

EntityDefinitionAssembler WARN  Custom SpatialContextFactory lib is not ready in classpath:com/vividsolutions/jts/geom/CoordinateSequenceFactory

Then my command line looks like:

java -cp "fuseki-server.jar:lib/jts-1.13.jar" org.apache.jena.fuseki.cmd.FusekiCmd -debug

I have downloaded jts-1.13.jar from here

Besides I would like to thank to Kai for pointing me in the right direction.

Note: I still have to fully understand the fields under spatial:EntityDefinition. I will try to edit with more information.