[ferret_users] derive bathymetry from 3D temperature data

[David Wang <climater@xxxxxxxxx>]

Hello Ferreters,

I'm going to define a two-dimensional bathymetry field from a 
three-dimensional temperature dataset (say Levitus climatology). 
Basically the value of the bathymetry will be set as ZBOXHI of the last 
grid point of non-missing values downward along the vertical direction. 
Can I do this in ferret?

Thanks,
- D.W.