メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.7875000 42.1708334, 142.7937500 42.1708334, 142.7937500 42.1750000, 142.7875000 42.1750000, 142.7875000 42.1708334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral