cell edges for 3-argument shade

[Keith Lindsay <klindsay@xxxxxxxxxxxx>]

Greetings,

I have 2 questions. The short versions are :

1) How does ferret generate boundaries for the 3-argument shade command?

2) Can these boundaries instead be user specified?

When a 3-argument shade command is issued, say for data on a curvilinear
grid, it appears that ferret is internally generating the boundaries or
edges of the 'cells'. How are these cell edges are generated? I cannot
find it documented in the Users Guide. I'm guessing it is a generalization
of what ferret does for rectilinear grids, which is to use midpoints of
the corresponding dimension variables, which leads to my next question.

For rectilinear grids, the 'midpoint technique' can be overridden with the
use of dimension edges. Is there a generalization of this that allows a
user to specify the edges for the 3-argument shade command?

Thanks,
Keith

************************************************************************
Keith Lindsay         http://www.cgd.ucar.edu/oce/klindsay/klindsay.html
email: klindsay@cgd.ucar.edu    phone: 303-497-1722    fax: 303-497-1700