メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.2625000 38.0875000, 138.2687500 38.0875000, 138.2687500 38.0916667, 138.2625000 38.0916667, 138.2625000 38.0875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral