メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6937500 42.8000000, 141.7000000 42.8000000, 141.7000000 42.8041667, 141.6937500 42.8041667, 141.6937500 42.8000000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral