メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((142.2875000 44.6291667, 142.2937500 44.6291667, 142.2937500 44.6333333, 142.2875000 44.6333333, 142.2875000 44.6291667)) ^^http://www.opengis.net/ont/geosparql#wktLiteral