メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.7125000 42.8958334, 141.7187500 42.8958334, 141.7187500 42.9000000, 141.7125000 42.9000000, 141.7125000 42.8958334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral