+[gis:located] > gis:indexed
+abstract mixin
+// either an EPSG code (e.g. EPSG:4326 for WGS 84) or a WKT representation
+- gis:srs (STRING) m
+// WKB
+- gis:bbox (BINARY) m
+// WKB
+- gis:centroid (BINARY) m
+// - gis:role (STRING)
+
+[gis:geometry] > nt:unstructured, gis:located
+- gis:wkb (STRING) m
+
+// GEOTOOLS
+[gis:feature] > nt:base
+mixin
+//- gis:relatedNode (REFERENCE) *
+
+[gis:featureSource] > nt:unstructured, mix:title