SREQP: A Solar Radiation Extraction and Query Platform for the Production and Consumption of Linked Data from Weather Stations Sensors

Listing 2

Example of federated query.

SELECT DISTINCT ?city_name ?quantityvalue

FROM <http://nadir.uc3m.es/solrad/dataset.rdf>

WHERE {

  SERVICE <http://nadir.uc3m.es:8890/solrad/sparql>   {

    ?station wgs84:location ?city.

    ?sensor ssn:onPlatform ?station.

    ?sensor a solrad:DirectIrradiancePyranometer.

    ?measurement ssn:observedBy ?sensor.

    ?measurement ssn:observationResult ?result.

    ?result ssn:hasValue ?value.

    ?value ssn:hasQuantityValue ?quantityvalue.

    ?measurement time:hasBeginning ?beginning.

    ?beginning time:inXSDDateTime ?timedate

    FILTER (?timedate = "2015-06-19T13:00:00.00+01:00"^∧∧xsd:#dateTime>)

  }

  SERVICE <http://dbpedia.org/sparql>  {

    ?city dcterms:subject category:Mediterranean_port_cities_and_towns_in_Spain;

     rdfs:label ?city_name.

    FILTER langMatches(lang(?city_name), "en")

  }

ORDER BY DESC (?quantityvalue)