メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.8875000 37.5000000, 138.8937500 37.5000000, 138.8937500 37.5041667, 138.8875000 37.5041667, 138.8875000 37.5000000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral