メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((131.3937500 31.8375000, 131.4000000 31.8375000, 131.4000000 31.8416667, 131.3937500 31.8416667, 131.3937500 31.8375000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral