メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.8687500 43.3958334, 141.8750000 43.3958334, 141.8750000 43.4000000, 141.8687500 43.4000000, 141.8687500 43.3958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral