メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.7750000 45.1500000, 141.7812500 45.1500000, 141.7812500 45.1541667, 141.7750000 45.1541667, 141.7750000 45.1500000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral