[ncl-talk] How to convert netcdf to grib format

Guido Cioni guidocioni at gmail.com
Mon Feb 13 03:52:42 MST 2017


A simple google search would lead you to the following posts. Now is your turn .

https://code.zmaw.de/boards/1/topics/248 <https://code.zmaw.de/boards/1/topics/248>

https://code.zmaw.de/boards/2/topics/1269 <https://code.zmaw.de/boards/2/topics/1269>

https://code.zmaw.de/boards/1/topics/3699 <https://code.zmaw.de/boards/1/topics/3699>





Guido Cioni
http://guidocioni.altervista <http://guidocioni.altervista/>.org

> On 13 Feb 2017, at 11:50, Guido Cioni <guidocioni at gmail.com> wrote:
> 
> Sorry, I didn't read carefully that you were trying to go from netcdf to grib... Just ignore the second part of the mail :) 
> 
> Guido Cioni
> http://guidocioni.altervista <http://guidocioni.altervista/>.org
> 
>> On 13 Feb 2017, at 11:49, Guido Cioni <guidocioni at gmail.com <mailto:guidocioni at gmail.com>> wrote:
>> 
>> Arunima, this is ncl-talk, not cdo-talk :) 
>> 
>> If CDO and NCL are having an hard time trying to convert your file *maybe* the problem is the file itself. Please read the appropriate documentation for CDO (https://code.zmaw.de/projects/cdo/wiki <https://code.zmaw.de/projects/cdo/wiki>).
>> By reading the CDO guide you would furthermore discover that the correct syntax of the command copy is the following:
>> cdo -f nc copy input_file.grb output_file.nc
>> 
>> and not the other way around. I suspect that won't fix the problem, but better starting from a clean state. 
>> 
>> Good luck
>> 
>> Guido Cioni
>> http://guidocioni.altervista <http://guidocioni.altervista/>.org
>> 
>>> On 13 Feb 2017, at 11:39, Arunima Singh <arunima at vassarlabs.com <mailto:arunima at vassarlabs.com>> wrote:
>>> 
>>> Hi,
>>> 
>>> I am running following command - 
>>> cdo -f grb setgrid,mygrid DET_10N20N_76E85E_2016111712.nc DET_10N20N_76E85E_2016111712.grib
>>> 
>>> But getting following error: 
>>> Warning (cgribexDefGrid) : The CGRIBEX library can not store fields on the used grid!
>>> 
>>> Error (cgribexDefGrid) : Unsupported grid type: generic
>>> 
>>> Am I doing something wrong, or is it because generic grid type is not supported.
>>> PFA files for reference.
>>> 
>>> Is there any other way to convert netcdf to grib2 format.
>>> 
>>> SAMPLE FILES:
>>> mygrid file ::
>>> 
>>> gridtype = generic
>>> xsize    = 73
>>> ysize    = 81
>>> xfirst   = 76
>>> xinc     = 0.005
>>> yfirst   = 20
>>> yinc     = 0.005
>>> 
>>> cdo griddes output::
>>> #
>>> # gridID 1
>>> #
>>> gridtype  = generic
>>> gridsize  = 81
>>> xsize     = 81
>>> #
>>> # gridID 2
>>> #
>>> gridtype  = generic
>>> gridsize  = 73
>>> xsize     = 73
>>> #
>>> # gridID 3
>>> #
>>> gridtype  = generic
>>> gridsize  = 5913
>>> xsize     = 73
>>> ysize     = 81
>>> cdo griddes: Processed 10 variables ( 0.00s )
>>> 
>>> 
>>> NetCDF file::
>>>  latitude = 20, 19.875, 19.75, 19.625, 19.5, 19.375, 19.25, 19.125, 19, 
>>>     18.875, 18.75, 18.625, 18.5, 18.375, 18.25, 18.125, 18, 17.875, 17.75, 
>>>     17.625, 17.5, 17.375, 17.25, 17.125, 17, 16.875, 16.75, 16.625, 16.5, 
>>>     16.375, 16.25, 16.125, 16, 15.875, 15.75, 15.625, 15.5, 15.375, 15.25, 
>>>     15.125, 15, 14.875, 14.75, 14.625, 14.5, 14.375, 14.25, 14.125, 14, 
>>>     13.875, 13.75, 13.625, 13.5, 13.375, 13.25, 13.125, 13, 12.875, 12.75, 
>>>     12.625, 12.5, 12.375, 12.25, 12.125, 12, 11.875, 11.75, 11.625, 11.5, 
>>>     11.375, 11.25, 11.125, 11, 10.875, 10.75, 10.625, 10.5, 10.375, 10.25, 
>>>     10.125, 10 ;
>>> 
>>>  longitude = 76, 76.125, 76.25, 76.375, 76.5, 76.625, 76.75, 76.875, 77, 
>>>     77.125, 77.25, 77.375, 77.5, 77.625, 77.75, 77.875, 78, 78.125, 78.25, 
>>>     78.375, 78.5, 78.625, 78.75, 78.875, 79, 79.125, 79.25, 79.375, 79.5, 
>>>     79.625, 79.75, 79.875, 80, 80.125, 80.25, 80.375, 80.5, 80.625, 80.75, 
>>>     80.875, 81, 81.125, 81.25, 81.375, 81.5, 81.625, 81.75, 81.875, 82, 
>>>     82.125, 82.25, 82.375, 82.5, 82.625, 82.75, 82.875, 83, 83.125, 83.25, 
>>>     83.375, 83.5, 83.625, 83.75, 83.875, 84, 84.125, 84.25, 84.375, 84.5, 
>>>     84.625, 84.75, 84.875, 85 ;
>>> 
>>> 
>>> On Mon, Feb 13, 2017 at 3:44 PM, Arunima Singh <arunima at vassarlabs.com <mailto:arunima at vassarlabs.com>> wrote:
>>> Hi,
>>> 
>>> I am running following command - 
>>> cdo -f grb setgrid,mygrid DET_10N20N_76E85E_2016111712.nc DET_10N20N_76E85E_2016111712.grib
>>> 
>>> But getting following error: 
>>> Warning (cgribexDefGrid) : The CGRIBEX library can not store fields on the used grid!
>>> 
>>> Error (cgribexDefGrid) : Unsupported grid type: generic
>>> 
>>> Am I doing something wrong, or is it because generic grid type is not supported.
>>> PFA files for reference.
>>> 
>>> Is there any other way to convert netcdf to grib2 format.
>>> 
>>> Thanks and Regards,
>>> Arunima Singh
>>> 
>>> On Mon, Feb 13, 2017 at 1:30 PM, Beáta Szábo-Takács <szabo.b at czechglobe.cz <mailto:szabo.b at czechglobe.cz>> wrote:
>>> 
>>> Hi,
>>> 
>>> It hard to see the grid type by ncdump results. Can you apply Climate Data Operator (CDO)? If yes, you can see the grid coordinates with the sinfo or griddes operators:
>>> 
>>> cdo sinfo file.nc <http://file.nc/>
>>> 
>>> cdo griddes file.nc <http://file.nc/>
>>> 
>>> You can create mygrid file by the following way:
>>> 
>>> cat > mygrid << EOF
>>> gridtype = 
>>> xsize    = 
>>> ysize    = 
>>> xfirst   = 
>>> xinc     = 
>>> yfirst   = 
>>> yinc     = 
>>> EOF
>>> I hope I could help you.
>>> 
>>> Beata
>>> 
>>> 
>>> From: Arunima Singh <arunima at vassarlabs.com <mailto:arunima at vassarlabs.com>>
>>> Sent: Monday, February 13, 2017 8:32:49 AM
>>> To: Beáta Szábo-Takács
>>> Cc: Barry Lynn; ncl-talk
>>> 
>>> Subject: Re: [ncl-talk] How to convert netcdf to grib format
>>>  
>>> Hi,
>>> 
>>> Thanks .
>>> Can you please tell me what to have in mygrid ?
>>> 
>>> My netcdf file has following variables : 
>>> netcdf DET_10N20N_76E85E_2016111712 {
>>> dimensions:
>>> lat = 81 ;
>>> lon = 73 ;
>>> time = 41 ;
>>> variables:
>>> float latitude(lat) ;
>>> latitude:units = "degrees_north" ;
>>> float longitude(lon) ;
>>> longitude:units = "degrees_east" ;
>>> float time(time) ;
>>> time:units = "hours since 2016-11-17 12Z" ;
>>> float \2m_temperature(time, lat, lon) ;
>>> \2m_temperature:units = "C" ;
>>> float \2m_relative_humidity(time, lat, lon) ;
>>> \2m_relative_humidity:units = "%" ;
>>> float mean_sea_level_pressure(time, lat, lon) ;
>>> mean_sea_level_pressure:units = "Pa" ;
>>> float \6hr_accumulated_precip(time, lat, lon) ;
>>> \6hr_accumulated_precip:units = "mm" ;
>>> float \10m_U_wind(time, lat, lon) ;
>>> \10m_U_wind:units = "m/s" ;
>>> float \10m_V_wind(time, lat, lon) ;
>>> \10m_V_wind:units = "m/s" ;
>>> float wind_magnitude(time, lat, lon) ;
>>> wind_magnitude:units = "m/s" ;
>>> float wind_direction(time, lat, lon) ;
>>> wind_direction:units = "degrees" ;
>>> }
>>> 
>>> 
>>> On Mon, Feb 13, 2017 at 12:56 PM, Beáta Szábo-Takács <szabo.b at czechglobe.cz <mailto:szabo.b at czechglobe.cz>> wrote:
>>> Hi,
>>> 
>>> According to CDO support:
>>> 
>>> The grid type generic means that the variables have either no grid information or the grid information is not supported in CDO.
>>> In both cases it is not possible to store the data in GRIB format. Here is a list of all supported CDO GRIB grid types:
>>> 
>>> Latitude/longitude grid
>>> Lambert conformal grid
>>> Gaussian latitude/longitude grid
>>> Rotated latitude/longitude grid
>>> Spherical Harmonic Coefficients
>>> Icosahedral-hexagonal GME grid
>>> You have to add the missing grid information with setgrid if there is no grid information in your file and the variables are stored on one of the above grids:
>>> 
>>> cdo -f grb setgrid,mygrid cc.nc <http://cc.nc/> cc.grb
>>> 
>>> You can check the grid information of the variables with the CDO function sinfo or griddes.
>>> 
>>>  
>>> 
>>> I hope I could help you.
>>> 
>>>  
>>> 
>>> Beata
>>> 
>>>  
>>> 
>>>  
>>> 
>>> From: Arunima Singh [mailto:arunima at vassarlabs.com <mailto:arunima at vassarlabs.com>] 
>>> Sent: Monday, February 13, 2017 8:16 AM
>>> To: Beáta Szábo-Takács <szabo.b at czechglobe.cz <mailto:szabo.b at czechglobe.cz>>
>>> Cc: Barry Lynn <barry.h.lynn at gmail.com <mailto:barry.h.lynn at gmail.com>>; ncl-talk <ncl-talk at ucar.edu <mailto:ncl-talk at ucar.edu>>
>>> 
>>> 
>>> Subject: Re: [ncl-talk] How to convert netcdf to grib format
>>> 
>>>  
>>> 
>>> I tried cdo - 
>>> 
>>> cdo -f grb copy DET_10N20N_76E85E_2016111712.nc DET_10N20N_76E85E_2016111712.grib
>>> 
>>>  
>>> 
>>> but i am getting following error :
>>> 
>>>  
>>> 
>>> Warning (cgribexDefGrid) : The CGRIBEX library can not store fields on the used grid!
>>> 
>>>  
>>> 
>>> Error (cgribexDefGrid) : Unsupported grid type: generic
>>> 
>>>  
>>> 
>>>  
>>> 
>>> On Mon, Feb 13, 2017 at 12:40 PM, Beáta Szábo-Takács <szabo.b at czechglobe.cz <mailto:szabo.b at czechglobe.cz>> wrote:
>>> 
>>> Hi,
>>> 
>>>  
>>> 
>>> I think you can convert netcdf to grib by CDO. Try the following operator:
>>> 
>>>  
>>> 
>>> cdo -f grb copy file.nc <http://file.nc/> file.grb
>>> 
>>>  
>>> 
>>> I hope it helps.
>>> 
>>>  
>>> 
>>> Beata
>>> 
>>>  
>>> 
>>> From: ncl-talk-bounces at ucar.edu <mailto:ncl-talk-bounces at ucar.edu> [mailto:ncl-talk-bounces at ucar.edu <mailto:ncl-talk-bounces at ucar.edu>] On Behalf Of Arunima Singh
>>> Sent: Monday, February 13, 2017 8:05 AM
>>> To: Barry Lynn <barry.h.lynn at gmail.com <mailto:barry.h.lynn at gmail.com>>
>>> Cc: ncl-talk <ncl-talk at ucar.edu <mailto:ncl-talk at ucar.edu>>
>>> Subject: Re: [ncl-talk] How to convert netcdf to grib format
>>> 
>>>  
>>> 
>>> Hi,
>>> 
>>>  
>>> 
>>> What i want is netcdf to grib2 format instead of grib to netcdf.
>>> 
>>>  
>>> 
>>> Thanks and Regards,
>>> 
>>> Arunima Singh
>>> 
>>>  
>>> 
>>>  
>>> 
>>> On Mon, Feb 13, 2017 at 12:31 PM, Barry Lynn <barry.h.lynn at gmail.com <mailto:barry.h.lynn at gmail.com>> wrote:
>>> 
>>> Hi:
>>> 
>>>  
>>> 
>>> I believe you can find the answer here:
>>> 
>>>  
>>> 
>>> http://www.ncl.ucar.edu/Applications/griball.shtml <http://www.ncl.ucar.edu/Applications/griball.shtml>
>>>  
>>> 
>>> On Mon, Feb 13, 2017 at 8:56 AM, Arunima Singh <arunima at vassarlabs.com <mailto:arunima at vassarlabs.com>> wrote:
>>> 
>>> Hi,
>>> 
>>>  
>>> 
>>> I have one netcdf file that i want to convert to grib format.
>>> 
>>> Can we do this conversion with ncl?
>>> 
>>>  
>>> 
>>> If yes, how?
>>> 
>>>  
>>> 
>>> Thanks and Regards,
>>> 
>>> Arunima Singh
>>> 
>>>  
>>> 
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>>> 
>>> 
>>>  
>>> 
>>> --
>>> 
>>> Barry H. Lynn, Ph.D
>>> 
>>> Senior Lecturer,
>>> 
>>> The Institute of the Earth Science, 
>>> The Hebrew University of Jerusalem, 
>>> Givat Ram, Jerusalem 91904, Israel 
>>> 
>>> Tel: 972 547 231 170
>>> Fax: (972)-25662581
>>> 
>>>  
>>> 
>>> C.E.O, Weather It Is, LTD
>>> Weather and Climate Focus
>>> http://weather-it-is.com <http://weather-it-is.com/>
>>> Jerusalem, Israel
>>> Local: 02 930 9525
>>> Cell: 054 7 231 170
>>> Int-IS: x972 2 930 9525
>>> US 914 432 3108
>>> 
>>>  
>>> 
>>>  
>>> 
>>> 
>>> 
>>> 
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>> 
> 

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