メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6812500 45.4000000, 141.6875000 45.4000000, 141.6875000 45.4041667, 141.6812500 45.4041667, 141.6812500 45.4000000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral