メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.2875000 38.1416667, 138.2937500 38.1416667, 138.2937500 38.1458334, 138.2875000 38.1458334, 138.2875000 38.1416667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral