メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.2375000 36.6875000, 138.2437500 36.6875000, 138.2437500 36.6916667, 138.2375000 36.6916667, 138.2375000 36.6875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral