メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.6375000 37.2791667, 138.6437500 37.2791667, 138.6437500 37.2833333, 138.6375000 37.2833333, 138.6375000 37.2791667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral