メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.1437500 43.9916667, 142.1500000 43.9916667, 142.1500000 43.9958334, 142.1437500 43.9958334, 142.1437500 43.9916667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral