メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.2375000 43.1375000, 141.2437500 43.1375000, 141.2437500 43.1416667, 141.2375000 43.1416667, 141.2375000 43.1375000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral