deploy virtuoso and load some data

a getting started on loading some dcat data

as described in EJPsoil wiki you can spin a local instance of virtuoso using this docker compose.

you can upload the zip attached (as extracted from https://nationaalgeoregister.nl) using quad-store-upload (in the linked data menu of virtuoso conductor), set the iri to some iri (you need it when querying the graph)

Run a sparql query from the sparql panel:

summary of graph

select distinct ?class (count(?thing) as ?numInstances) where {
  graph <http://soilwise-he.eu> {
  ?thing a ?class .
  }
}

datasets per organisation

PREFIX dcat: <http://www.w3.org/ns/dcat#>
PREFIX dcterms: <http://purl.org/dc/terms/>

SELECT ?organization (count (distinct ?dataset) as ?numDatasets)
(count (distinct ?distribution) as ?numDistributions)
WHERE {
  graph <http://soilwise-he.eu> {
 ?dataset a dcat:Dataset ;
          dcterms:publisher ?organization ;
                dcat:distribution ?distribution .  }
} 
group by ?organization
order by desc(?numDatasets)
limit 20

count by license

PREFIX dcat: <http://www.w3.org/ns/dcat#>
PREFIX dct: <http://purl.org/dc/terms/>

SELECT ?url (count(distinct ?dataset) as ?count) WHERE {
SELECT (IRI(?name) AS ?url) ?dataset WHERE {
            ?dataset a dcat:Dataset .
            ?dataset dct:license ?name
            FILTER(isLiteral(?name))
        }
} GROUP BY ?url

count by format

PREFIX dcat: <http://www.w3.org/ns/dcat#>
PREFIX dct: <http://purl.org/dc/terms/>

SELECT ?format (count(distinct ?dataset) as ?count) WHERE {
SELECT ?dataset ?format WHERE {
  ?dataset dcat:distribution ?distribution .
  ?distribution dct:format ?format .
}
} GROUP BY ?format

Exported records from NGR https://www.nationaalgeoregister.nl/geonetwork/srv/api/rdf.search?from=100. Some observations:

Max number of records exported is 100, you need to crawl by 100 (from=100,200,300) to fetch all
Some of those iterations fail when loading on virtuoso (invalid graph data)

Download: rdf200.zip

soilwise-he / triplestore-virtuoso

deploy virtuoso and load some data #3