Query 0 - Find_Closest_Populated_Place:

PREFIX dataset: <http://geographica.di.uoa.gr/dataset/>
PREFIX geof: <http://www.opengis.net/def/function/geosparql/> 
PREFIX geo: <http://www.opengis.net/ont/geosparql#> 
PREFIX opengis: <http://www.opengis.net/def/uom/OGC/1.0/>
PREFIX geonames: <http://www.geonames.org/ontology#> 
 
SELECT ?f (geof:distance(?cGeoWKT, "GIVEN_POINT_IN_WKT"^^geo:wktLiteral, opengis:metre) as ?distance)
WHERE { 
	GRAPH dataset:geonames { 
		?f geonames:featureCode geonames:P.PPL.
		?f geonames:hasGeometry ?cGeo. 
		?cGeo geonames:asWKT ?cGeoWKT. 
	}
} 
ORDER BY ASC(?distance) 
LIMIT 1 


Query 1 - Find_Closest_Motorway:

PREFIX dataset: <http://geographica.di.uoa.gr/dataset/>
PREFIX geof: <http://www.opengis.net/def/function/geosparql/> 
PREFIX geo: <http://www.opengis.net/ont/geosparql#> 
PREFIX opengis: <http://www.opengis.net/def/uom/OGC/1.0/>
PREFIX rdf: <http://www.w3.org/1999/02/22-rdf-syntax-ns#> 
PREFIX lgd: <http://linkedgeodata.org/ontology/> 
 
SELECT ?c ?type ?label (geof:distance(?cGeoWKT, "GIVEN_POINT_IN_WKT"^^geo:wktLiteral, opengis:metre) as ?distance) ?cGeoWKT 
WHERE { 
	GRAPH dataset:lgd { 
	?c rdf:type lgd:Motorway.
	?c rdfs:label ?label.
	?c lgd:hasGeometry ?cGeo. 
	?cGeo lgd:asWKT ?cGeoWKT. 
	}
} 
ORDER BY ASC(?distance) 
LIMIT 1