Re: [ferret_users] define grid

[Ansley Manke <ansley.b.manke@xxxxxxxx>]

Hi David,
It looks to me as if what you may want is a SET REGION command, rather 
than DEFINE GRID:

 let imax = `raz[d=1],return=iend`
 let jmax = `raz[d=1],return=jend`
 set region/I=2:`imax-1`/J=2:`jmax-1`

You can also use DEFINE REGION to give your region a name, and use that 
name to store a particular region setting.


To use DEFINE GRID, you need axis names, not index ranges.  So the 
following would keep the Z and T axis of the grid of your variable, and 
create new axes using the same units and coordinates as the original 
axis for the variable.

 let imax = `raz[d=1],return=iend`
 let jmax = `raz[d=1],return=jend`
 define axis/x/units=`raz[d=1],return=xunits`  newxax = 
x[gx=raz[d=1],i=2:`imax-1`]
 define axis/y/units=`raz[d=1],return=yunits`  newyax = 
y[gx=raz[d=1],j=2:`jmax-1`]
 define grid/like=raz[d=1]/x=newxax/y=newyax newgrid

Ansley

David Wang wrote:

> Hello Ferreters,
>
> I'm intending to use a subset of an existing grid to define a new 
> grid, onto which another variable will be regridded by the 
> transformation @ASN. I tried something like:
>
> let imax = `raz[d=1],return=iend`
> let jmax = `raz[d=1],return=jend`
> define grid/like=raz[d=1]/I=2:`imax-1`/J=2:`jmax-1` newgrid
>
> but it didn't go through, and  told me:
> **ERROR: unknown command qualifier: I=2:`imax-1`
>
> Any hints?
>
> Thanks,
> - David