メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.4125000 43.1875000, 141.4187500 43.1875000, 141.4187500 43.1916667, 141.4125000 43.1916667, 141.4125000 43.1875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral