geometry_dump — A composite type used to describe the parts of complex geometry.
geometry_dump is a
composite data type
containing the fields:
geom - a geometry representing a component of the dumped geometry.
The geometry type depends on the originating function.
path[] - an integer array
that defines the navigation path within the dumped geometry to the geom component.
The path array is 1-based (i.e. path[1] is the first element.)
It is used by the ST_Dump* family of functions as an output type to explode a complex geometry into its
constituent parts.