メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.4875000 35.5708334, 138.4937500 35.5708334, 138.4937500 35.5750000, 138.4875000 35.5750000, 138.4875000 35.5708334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral