メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.7937500 42.7791667, 141.8000000 42.7791667, 141.8000000 42.7833333, 141.7937500 42.7833333, 141.7937500 42.7791667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral