メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.8187500 37.5708334, 138.8250000 37.5708334, 138.8250000 37.5750000, 138.8187500 37.5750000, 138.8187500 37.5708334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral