The finest frame when one code of it sits on each leaftable row, and the
key column otherwise. A NestedScale built from a nested hierarchy is the
first kind; a timescales::Calendar is the second, because its timeslices
are combinations of its frames rather than codes of any one of them.
scale_atom_level(x)A NestedScale.
A single string – a frame name, or the key.
Needed by the dimension packages: it is the frame to pass to
join_scale() or recast_scale() for data keyed at the atoms.
scale_atom_level(scale_example())
#> [1] "unit"