[ferret_users] how to set a discontinuous region

[igaratza@xxxxxxxxxxxxxxxxxxxx]

Hi,

I want to define a region for mid-latitudes of both hemispheres, let's say
between 20-40 S and 20-40 N.
I guess should be easy, but I don't find a way to do it. For ploting is no
problem, I define first one hemisphere and after the other:

set region/y=-40:-20/x=-180:180
shade temp[d=1,l=1]
set region/y=40:20/x=-180:180
shade/ov temp[d=1,l=1]

But I need some statistic of this two regions together, and this way does not
work.
Any suggestion?

Thanks