メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.5937500 42.8958334, 141.6000000 42.8958334, 141.6000000 42.9000000, 141.5937500 42.9000000, 141.5937500 42.8958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral