GraphDB - Federated Query - sparql

Question

I would like to know how to perform a federated search on GraphDB. For example, to insert the code below in GraphDB, how should I do it? The idea is to add the content below to my local GraphDB.
#Locations of air accidents in wikidata - https://query.wikidata.org/
SELECT ?label ?coord ?place
WHERE
{
?subj wdt:P31 wd:Q744913 .
?subj wdt:P625 ?coord .
?subj rdfs:label ?label
filter (lang(?label) = "en")
}

Answer 1

Posting #UninformedUser's comment as an answer for better readability.
SPARQL 1.1 offers the SERVICE feature, described here. You can use it to perform federated queries against Wikidata directly inside of GraphDB.
SELECT * WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}

Answer 2

To insert the data to your local GraphDB, use something like this:
INSERT {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
} WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
wdt:P625 ?coord ;
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}
However, you'd probably want to unpack the coordinates and use some ontology that's easier to understand, eg:
PREFIX wgs: <http://www.w3.org/2003/01/geo/wgs84_pos#> # see http://prefix.cc/wgs.sparql
INSERT {
?subj a :AirAccident;
wgs:lat ?lat; wgs:long ?long;
rdfs:label ?label
} WHERE {
SERVICE <https://query.wikidata.org/sparql> {
?subj wdt:P31 wd:Q744913 ;
p:P625/psv:P625 [wikibase:geoLatitude ?lat; wikibase:geoLongitude ?long];
rdfs:label ?label
FILTER (lang(?label) = "en")
}
}
For the p:P625, psv:P625, wikibase:geoLatitude stuff, see https://github.com/nichtich/wdq#wikidata-ontology (and if you install it, wdq help ontology gives this color-coded)