メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.4187500 37.2458334, 138.4250000 37.2458334, 138.4250000 37.2500000, 138.4187500 37.2500000, 138.4187500 37.2458334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral