メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.2125000 36.7875000, 138.2187500 36.7875000, 138.2187500 36.7916667, 138.2125000 36.7916667, 138.2125000 36.7875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral