メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.9187500 42.7458334, 141.9250000 42.7458334, 141.9250000 42.7500000, 141.9187500 42.7500000, 141.9187500 42.7458334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral