メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.7875000 37.1791667, 138.7937500 37.1791667, 138.7937500 37.1833333, 138.7875000 37.1833333, 138.7875000 37.1791667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral