template with %ch

[Mateus Teixeira]

Thanks Jennifer,

The problem was that I forgot UNPACK option to provide the
'scale_factor' and 'add_offset' values.
Now it's working perfectly.

Mateus

Jennifer Adams a écrit :
> Mateus,
> You need to change your variable declaration for dtype netcdf files. It
> should be something like this:
>    air 0 t,y,x air temperature
> Check the output from ncdump on your netcdf file to make sure the
> variable 'air' is not defined in the Z dimension. Also, with a dtype
> short, you may run into problems with undef handling -- the undef 32766
> will be converted into a float value and may interfere with results of
> your data analysis -- better way to do it is to give a new undef value
> and the name of the undef attribute (e.g. "missing_value"):
>    UNDEF -1e+20 missing_value
> This way, as GrADS does the I/O, it will retrieve the missing value for
> your variable, test against it, and if it's a match, it will set the
> data value to -1e+20.
>
> The CHSUB entries look fine, but if you suspect them, then leave them
> out for testing purposes and write a descriptor without templating and
> see if you can open and display air temperatures from the first file.
>
> Jennifer
>
> p.s. In general, for questions about netcdf files, please include the
> output from ncdump.
>
> On Aug 16, 2006, at 10:17 AM, Mateus Teixeira wrote:
>
>> Dear GrADS users,
>>
>> I'm trying to use the new template option %ch to open 3
>> NCEP/NCAR-Reanalysis files which contain the air temperature at 1000
>> hPa. Their names are: T1000_HS_1985_1990.nc; T1000_HS_1991_1995.nc; and
>> T1000_HS_1996_2003.nc.
>>
>> Reading GrADS docs I saw an example to open netcdf files and made my
>> control file as follow:
>>
>> DSET ^T1000_HS_%ch.nc
>> OPTIONS template
>> DTYPE netcdf
>> CHSUB     1   8764 1985_1990
>> CHSUB  8765  16068 1991_1995
>> CHSUB 16069  27756 1996_2003
>> UNDEF 32766
>> XDEF 144 linear   0 2.5
>> YDEF  37 linear -90 2.5
>> ZDEF   1 linear 1000 1
>> TDEF 27756 linear 00z01jan1985 4hr
>> VARS 1
>> air 1 99 Air Temperature
>> ENDVARS
>>
>> However, when I tried to display this variable I got an error message:
>>
>> NetCDF Read Error (ncvarget) for data type NC_SHORT
>> Data Request Error:  Error for variable 'air'
>>  Error ocurred at column 1
>> DISPLAY error:  Invalid expression
>>  Expression = air
>>
>> The variable name is the same of the netCDF files, but I think that I
>> missed something to GrADS gets properly the netCDF file.
>>
>> Thanks in advance!
>>
>> --
>> Mateus da Silva Teixeira
>> Doutorando em Meteorologia - CPTEC/INPE
>> e-mail: mtex2k3 at yahoo.com.br, mateus at cptec.inpe.br
>> site: www.geocities.com/mtex2k3
>>
>>
>>
>> _______________________________________________________
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>>
> --
> Jennifer Miletta Adams
> Center for Ocean-Land-Atmosphere Studies (COLA)
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705 USA
> jma at cola.iges.org
>
--

Mateus da Silva Teixeira
Doutorando em Meteorologia - CPTEC/INPE
e-mail: mtex2k3 at yahoo.com.br, mateus at cptec.inpe.br
site: www.geocities.com/mtex2k3



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