メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.5750000 42.8750000, 141.5812500 42.8750000, 141.5812500 42.8791667, 141.5750000 42.8791667, 141.5750000 42.8750000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral