メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.8000000 45.1958334, 141.8062500 45.1958334, 141.8062500 45.2000000, 141.8000000 45.2000000, 141.8000000 45.1958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral