メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6937500 38.9958334, 141.7000000 38.9958334, 141.7000000 39.0000000, 141.6937500 39.0000000, 141.6937500 38.9958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral