Re: [ferret_users]"save" changes the variable type

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

Hi Zhen,
No, at present there is not a way to set the type of variables written 
by Ferret. All variables are converted to single precision float (and 
coordinate variables to double precision). 
We have a project underway which will start to give you control over 
these things.  A version to be released soon, this month I hope, will 
keep the upper-and lower-case form of your variable names. I don't yet 
know whether the option to  retain the original type of the data, or set 
the type that's written will be in this upcoming release or whether 
it'll need to wait for a future release, but it should be something we 
can do in a future version.

I hope somebody can help with your question about ncks -- anyone?


Ansley

zhen.li@gsfc.nasa.gov wrote:

> Dear Ferret users,
>
> Recently I noticed that using ferret "save" command to extract 
> variables from netcdf file does not
> preserve the variable types in the original file. For example, 
> variable "temp" is defined as "short temp(time, zt_ocean, yt_ocean, 
> xt_ocean) in my original file".  After I open this file and do "save 
> temp" to another file, "temp" is defined
> as "float TEMP(TIME, ZT_OCEAN, YT_OCEAN, XT_OCEAN)". Also, ZT_OCEAN, 
> YT_OCEAN, XT_OCEAN are all
> declared as "double" in stead of  float. Of course, the variables are 
> all capitalized. I wonder if there is any way to force
> the ferret to write out  the variables as is?
>
> I know that this is not a big deal. But, the file saved by ferret 
> actually doubles the size.  I'd like to keep my file size as small as 
> possible.
>
> Some of you might suggest that I use "ncks" to extract the variables. 
> However, I got an error message when I use
> ncks to retrieve the variable.
> "ncks: ERROR unable to determine method for remote retrieval of 
> ocean_month_1980_01.nc". The ncks works well
> when I use it on Compaq super computer where the 
> ocean_month_1980_01.nc was created. But, once after I
> transfer the file to a local Linux machine, it no longer works. Does 
> anyone know why this is the case?
>
> Thank you in advance for your help!
>
> Zhen