メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((141.7187500 45.3833333, 141.7250000 45.3833333, 141.7250000 45.3875000, 141.7187500 45.3875000, 141.7187500 45.3833333)) ^^http://www.opengis.net/ont/geosparql#wktLiteral