メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.6687500 37.2916667, 138.6750000 37.2916667, 138.6750000 37.2958334, 138.6687500 37.2958334, 138.6687500 37.2916667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral