Re: syntax of reading netCDF4 files with groups

Wenshan,

There is a problem with getfilegrpnames, otherwise, the second script below will work.

Mean while, you can use "ncl_filedump X.nc | grep group" to get the group names.

Then use script:
 f = addfile ("X.nc" , "r") ; could also have ccm, grb or hdf suffux

;(0) snd_LImon_ACCESS1-0_historical_all-ens_GN_monthly_anomaly
;(1) snd_LImon_CCSM4_historical_all-ens_GN_monthly_anomaly
;(2) snd_LImon_CESM1-CAM5_historical_all-ens_GN_monthly_anomaly
;(3) snd_LImon_CESM1-FASTCHEM_historical_all-ens_GN_monthly_anomaly
;(4) snd_LImon_CESM1-WACCM_historical_all-ens_GN_monthly_anomaly
;(5) snd_LImon_CMCC-CM_historical_all-ens_GN_monthly_anomaly
;(6) snd_LImon_CMCC-CMS_historical_all-ens_GN_monthly_anomaly
;(7) snd_LImon_CSIRO-Mk3-6-0_historical_all-ens_GN_monthly_anomaly

 gn = "snd_LImon_ACCESS1-0_historical_all-ens_GN_monthly_anomaly"
 
 g = f=>$gn$ ; read the group to memory
         
 printVarSummary(g)

 vNames = getfilevarnames (g) ; get names of all groups on file
 nvNames = dimsizes (vNames) ; number of vars in the group
      
 print (nvNames) ; print number of variables in group
 print (vNames) ; print variable name in group

 do m=0,nvNames-1
       print("===========================================================")
       print("Variable Number: " + m)
       v = g->$vNames(m)$ ; read the variable to memory
       printVarSummary(v)
       delete(v)
 end do

to read variables.

We are working on getfilegrpnames, and hope to fix it soon.

Regards,

Wei

huangwei@ucar.edu
VETS/CISL
National Center for Atmospheric Research
P.O. Box 3000 (1850 Table Mesa Dr.)
Boulder, CO 80307-3000 USA
(303) 497-8924

-------------
 f = addfile ("X.nc" , "r") ; could also have ccm, grb or hdf suffux

;print(f)

 gNames = getfilegrpnames (f) ; get names of all groups on file
 ngNames = dimsizes (gNames) ; number of groups on the file
      
 print (ngNames) ; print number of group names on file
 print (gNames) ; print group names on file
      
 do n=0,ngNames-1 ; loop thru each group
    print("--------------------------------------------------------")
    print("Group Number: " + n)

    g = f=>$gNames(n)$ ; read the group to memory
         
    printVarSummary(g)

    vNames = getfilevarnames (g) ; get names of all groups on file
    nvNames = dimsizes (vNames) ; number of vars in the group
      
    print (nvNames) ; print number of variables in group
    print (vNames) ; print variable name in group

    do m=0,nvNames-1
       print("===========================================================")
       print("Variable Number: " + m)
       v = g->$vNames(m)$ ; read the variable to memory
       printVarSummary(v)
       delete(v)
    end do

   ;[SNIP]
         
    delete(g)
 end do

On Jan 4, 2013, at 4:38 PM, Wei Huang wrote:

> Wenshan,
>
> I'll check and get back to you.
>
> Thanks,
>
> Wei
>
> huangwei@ucar.edu
> VETS/CISL
> National Center for Atmospheric Research
> P.O. Box 3000 (1850 Table Mesa Dr.)
> Boulder, CO 80307-3000 USA
> (303) 497-8924
>
>
>
>
>
>
> On Jan 4, 2013, at 4:32 PM, Wenshan Wang wrote:
>
>> The version of NCL I am using is: 6.1.0-08Oct2012_1119
>>
>> I've put my sample file on the ftp:
>> incoming/snd_LImon_all-model_historical_all-ens_GN_monthly-anomaly.nc
>>
>> Thank you!
>>
>> Best,
>> Wenshan
>>
>>
>> On Fri, Jan 4, 2013 at 3:15 PM, Wenshan Wang <wenshanw@uci.edu> wrote:
>> Dear all,
>>
>> I am trying to read netCDF4 files with groups, following the example given on the page of 'getfilegrpnames'.
>> Here it is:
>> f = addfile ("X.nc" , "r") ; could also have ccm, grb or hdf suffux
>> gNames = getfilegrpnames (f) ; get names of all groups on file
>>
>> nNames = dimsizes (gNames) ; number of groups on the file
>>
>> print (nNames) ; print all group names on file
>>
>> do n=0,nNames-1 ; loop thru each group
>> v = f->$gNames(n)$ ; read the group to memory
>>
>> dimv = dimsizes(v) ; dimension size of the group
>> rank = dimsizes(dimv) ; rank [ie: number of dimensions]
>>
>> [SNIP]
>>
>> delete (v)
>> delete (rank)
>> end do
>>
>> However, if I followed the example and use:
>> v = f->$gNames(n)$
>> It will result in:
>> fatal:["Execute.c":5709]:variable (snc_LImon_bcc-csm1-1_historical_all-ens_clm) is not in file (fin)
>>
>> Instead, if I use:
>> gg = fin=>$gn(j)$
>> dd = gg->$var(i)$
>> It can read what I want, but there is an error message:
>> fatal:NclNetCDF4: Could not reopen the file (~/data/cmip5/output/4plot/snd_LImon_all-model_historical_all-ens_clm.nc) for reading
>>
>> So, what syntax should I use to read variables in groups?
>>
>> Thank you very much!
>> Happy New Year!
>>
>> Best,
>> Wenshan
>>
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Received on Fri Jan 4 20:23:45 2013