メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.9000000 45.0125000, 141.9062500 45.0125000, 141.9062500 45.0166667, 141.9000000 45.0166667, 141.9000000 45.0125000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral