メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6000000 42.8375000, 141.6062500 42.8375000, 141.6062500 42.8416667, 141.6000000 42.8416667, 141.6000000 42.8375000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral