Feature index of the “parent” boundary enclosing this one, or -1 if an outermost boundary.

A McMeasure object.  

object.miRgnNestedWithinIndex

The miRgnNestedWithinIndex Property syntax has these parts:

This is a non-standard measurement because the type of the measurement is a Long index value rather than a Double numeric value. This measurement is basically a duplicate of the NestedWithin property

Each boundary can have at most one “parent” boundary that encloses it. This measurement reports the feature index of any enclosing parent boundary. Outermost boundaries will have a miRgnNestedWithinIndex of -1.

Nesting is based on boundary polygon computations where it is assumed that boundaries are either completely enclosed or not enclosed at all. For regions that overlap without being completely nested, the nesting relationship is ambiguous: either feature may be considered the parent or they may be considered not nested at all.

Note that a “hole” and a “nested region” are different things. Holes have no effect on this measurement unless they correspond to feature boundaries (and they usually will not). See the Holes and NestedWithin properties for more discussion.