Re: [ferret_users] bound variable detected as variable

[Marco Steinacher <steinacher@xxxxxxxxxxxxxxxx>]

Hi Patrick,

It seems that ferret does not use the bounds variable because your depth
axis has only one point. When I add another one (eg. at z=15 with bounds
at z=10 and z=20) the bounds are used correctly.

With only one grid cell Ferret apparently assumes a regular grid with
boundaries at z=4.5 and z=5.5 (probably in order to have weight=1). When
you save your data Ferret is using these bounds values. You can check
which boundaries Ferret is using with

 list zboxlo[g=SOSALINE_GLOBAL],zboxhi[g=SOSALINE_GLOBAL]

As a workaround you could extend the z-axis with

define axis/z/bounds/unit=meters `SOSALINE_GLOBAL,r=zaxis` = \
{5,15},{-0.000244140625,10.000244140625},{10.000244140625,20}

Then, the boundaries are treated as you are expecting.

Marco



Brockmann Patrick wrote:
> Hi all,
> 
> I have noticed that when a boundarie variable is present in a netcdf file,
> ferret detects this "associate" coordinate variable as a "classic"
> variable.
> 
> Consequence in my scripts, the use of
> yes? shade `..varnames[i=1]`
> to produce a shade with the first variable found in a file becomes not
> usable
> since ferret takes the boundaries variable.
> 
> I have also saved a file with /bounds qualifier
> and noticed that boundaries have been changed
> 
> Initially I have:
> DEPTH1_1 = 5 ;
> DEPTH1_1_bnds =
>  -0.000244140625, 10.000244140625 ;
> 
> After a
> yes? save/clobber/bounds/file=new.nc SOSALINE_GLOBAL
> 
> I get a
> DEPTH1_1 = 5 ;
> DEPTH1_1_bnds =
>  4.5, 5.5 ;
> 
> I do not understand why ferret has changed those values.
> Note that when I use /bounds qualifier, I also save bounds
> even when axis is regular. Is there a way to control the write
> of boundarie variables for each axis (ie qualifiers XBOUNDS, YBOUNDS,
> ZBOUNDS, TBOUNDS).
> 
> Download,
> http://dods.ipsl.jussieu.fr/brocksce/ferret_bugs/OCE_sosaline_global_ave.nc
> and try
> http://dods.ipsl.jussieu.fr/brocksce/ferret_bugs/err620_bnds.jnl
> 
> Tests made with ferret v620 (Linux 32bits)
> 
> Thanks gor any help on this topic.
> Patrick
> 


-- 
***************************************
Marco Steinacher

Climate and Environmental Physics
Physics Institute, University of Bern
Sidlerstrasse 5, CH-3012 Bern

Phone ++41 (0)31 631 34 02
Fax   ++41 (0)31 631 87 42
steinacher@xxxxxxxxxxxxxxxx
http://www.climate.unibe.ch/
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