メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6187500 45.1458334, 141.6250000 45.1458334, 141.6250000 45.1500000, 141.6187500 45.1500000, 141.6187500 45.1458334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral