メタデータ名 polygon
<http://xmlns.oracle.com/rdf/geo/srid/4612> POLYGON((138.4937500 38.2708334, 138.5000000 38.2708334, 138.5000000 38.2750000, 138.4937500 38.2750000, 138.4937500 38.2708334)) ^^http://www.opengis.net/ont/geosparql#wktLiteral