メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.3187500 43.8833333, 142.3250000 43.8833333, 142.3250000 43.8875000, 142.3187500 43.8875000, 142.3187500 43.8833333)) ^^http://www.opengis.net/ont/geosparql#wktLiteral