メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.3937500 37.9708334, 138.4000000 37.9708334, 138.4000000 37.9750000, 138.3937500 37.9750000, 138.3937500 37.9708334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral