メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.6187500 42.8875000, 141.6250000 42.8875000, 141.6250000 42.8916667, 141.6187500 42.8916667, 141.6187500 42.8875000)) ^^http://www.opengis.net/ont/geosparql#wktLiteral