メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.6187500 42.2250000, 142.6250000 42.2250000, 142.6250000 42.2291667, 142.6187500 42.2291667, 142.6187500 42.2250000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral