メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.4187500 42.9500000, 141.4250000 42.9500000, 141.4250000 42.9541667, 141.4187500 42.9541667, 141.4187500 42.9500000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral