メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((131.2375000 31.4750000, 131.2437500 31.4750000, 131.2437500 31.4791667, 131.2375000 31.4791667, 131.2375000 31.4750000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral