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Re: [ferret_users] SAVE and dimensionality



Hi all,
This isn't something we've seen before. Ryo and I will look into it a bit more and see if we can track down what's happening.

Ansley

Ryo Furue wrote:
Hi Ferreters,

I'm puzzled.  The SAVE command sometimes seems to reduce
the x-dimension without being told to do so.  In the following
example, I try to save a time-average of a 4D variable:

!!>>>> BEGIN SESSION >>>>>>>>>>>>>>>>>>>>>>
$ ferret
        NOAA/PMEL TMAP
        FERRET v6.1
        Linux(g77) 2.6.9-22. - 03/26/08
         8-Mar-09 16:00

set mode grat:dash
yes? use "http://. . . ./temp"
yes? show data
     currently SET data sets:
    1> http://. . . ./temp  (default)
 name     title                             I         J         K         L
 TEMP     potential temperature            1:3600    1:1500    1:54      1:72

yes? set memory/size=400
 Cached data cleared from memory
set mode grat:dash
yes? save/file=tmp.nc temp[l=1:2@ave]
 LISTing to file tmp.nc
yes?
!!<<<< END SESSION <<<<<<<<<<<<<<<<<<<<<<<<

But, the ncdump -h indicates that the variable in the
new file has a dimension of 1 x 1500 x 54, as can be seen
in the attached output.

I plotted the new variable on Ferret.  It seemed
to contain only the meridional section at i=1 (x=0.1E).

I tried a few other 4D fields but couldn't reproduce this
behavior.

A workaround seems to be

   yes? save/file=tmp.nc temp[i=1:3600,l=1:2@ave]

Regards,
Ryo
--------------
netcdf tmp {
dimensions:
        LON1_1 = 1 ;
        LAT = 1500 ;
        LEV = 54 ;
        bnds = 2 ;
variables:
        double LON1_1(LON1_1) ;
                LON1_1:units = "degrees_east" ;
                LON1_1:long_name = "longitude" ;
                LON1_1:modulo = 360. ;
                LON1_1:point_spacing = "even" ;
                LON1_1:axis = "X" ;
        double LAT(LAT) ;
                LAT:units = "degrees_north" ;
                LAT:long_name = "latitude" ;
                LAT:point_spacing = "even" ;
                LAT:axis = "Y" ;
        double LEV(LEV) ;
                LEV:units = "meters" ;
                LEV:positive = "down" ;
                LEV:long_name = "altitude" ;
                LEV:point_spacing = "uneven" ;
                LEV:axis = "Z" ;
                LEV:bounds = "LEV_bnds" ;
        double LEV_bnds(LEV, bnds) ;
        float TEMP(LEV, LAT, LON1_1) ;
                TEMP:missing_value = -1.e+34f ;
                TEMP:_FillValue = -1.e+34f ;
                TEMP:long_name = "potential temperature" ;
                TEMP:long_name_mod = "T=30-DEC-0045 12:00:01-MAR-0046 00:00@AVE" ;
                TEMP:history = "From temp" ;

// global attributes:
                :history = "FERRET V6.1    8-Mar-09" ;
                :Conventions = "CF-1.0" ;
}


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