メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.4625000 36.3750000, 138.4687500 36.3750000, 138.4687500 36.3791667, 138.4625000 36.3791667, 138.4625000 36.3750000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral