メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.7375000 45.3875000, 141.7437500 45.3875000, 141.7437500 45.3916667, 141.7375000 45.3916667, 141.7375000 45.3875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral