メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.3000000 44.6458334, 142.3062500 44.6458334, 142.3062500 44.6500000, 142.3000000 44.6500000, 142.3000000 44.6458334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral