メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.3875000 38.2291667, 138.3937500 38.2291667, 138.3937500 38.2333333, 138.3875000 38.2333333, 138.3875000 38.2291667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral