メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6875000 43.1791667, 141.6937500 43.1791667, 141.6937500 43.1833333, 141.6875000 43.1833333, 141.6875000 43.1791667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral