メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.3937500 38.0541667, 138.4000000 38.0541667, 138.4000000 38.0583333, 138.3937500 38.0583333, 138.3937500 38.0541667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral