メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.4437500 37.9958334, 138.4500000 37.9958334, 138.4500000 38.0000000, 138.4437500 38.0000000, 138.4437500 37.9958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral