[gradsusr] netCDF control file

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From: bari at iap-kborn.de
To: gradsusr at gradsusr.org
Date: Tue, 9 Nov 2010 13:37:29 +0100
Subject: Re: [gradsusr] netCDF control file
















Dear Heiner, 

Grads 2.0  in our server is now changed and it is compiled with
netCDF support.

When I tried:

>sdfopen ures.nc 

it says: 

 >Scanning self-describing file:  ures.nc

gadsdf: SDF file has no discernable X coordinate.

When I try: 

>xdfopen ures.ctl

>Scanning Descriptor File:  ures.ctl

gadsdf: Lon dimension dimension1 is not an SDF dimension.

SDF Descriptor file ures.ctl was not successfully opened &
parsed. 

 

---Matlab fwrite, I tried it but couldn’t manage. 

Thank you

Deniz



Von:
gradsusr-bounces at gradsusr.org [mailto:gradsusr-bounces at gradsusr.org] Im
Auftrag von Heiner Körnich

Gesendet: Montag, 8. November 2010 17:07

An: GrADS Users Forum

Betreff: Re: [gradsusr] netCDF control file



 

Hi Deniz,



when you write recognized "sdfopen" or "xdfopen", do you
mean that grads does not know the command? Is your grads-version compiled with
netcdf-support?



It is certainly a good thing to create netcdf-files, as they are
self-descriptive. But still you could write binary data from matlab with the
command fwrite:

http://www.mathworks.com/help/techdoc/ref/fwrite.html



Then you have to follow the logic of grads binary files, ie. first longitude,
then latitude, then height, then time, as described in the manual.



So far,

Heiner



On Mon, Nov 8, 2010 at 4:25 PM, Deniz Demirhan Bari <bari at iap-kborn.de> wrote:





Hello Heiner, 

Thank you for your mail. I tried 'sdfopen ures.nc'  but neither grads 2.0 nor grads
1.8 recognized sdfopen. Then I  prepared a control file as below, by
looking at the “CDO sinfo ures.nc”.
 Then tried  “xdfopen ures.ctl” but none of the grads
versions recognized xdfopen again. 

*

DSET  ^ures.nc

DTYPE  netcdf

UNDEF  -9e+33

XDEF dimension1  96 LINEAR 0.000000
3.750000

YDEF dimension2  48 LEVELS -87.159
-83.479 -79.777 -76.070 -72.362 -68.652 



              
-64.942 -61.232 -57.521 -53.810 -50.099 -46.389 

              
-42.678 -38.967 -35.256 -31.545 -27.833 -24.122 

              
-20.411 -16.700 -12.989  -9.278  -5.567  -1.856 

               
 1.856   5.567   9.278  12.989  16.700 
20.411 

               
24.122  27.833  31.545  35.256  38.967  42.678 

               
46.389  50.099  53.810  57.521  61.232  64.942 

               
68.652  72.362  76.070  79.777  83.479  87.159 



ZDEF dimension3  114 LINEAR 1 1

TDEF dimension4  1 LINEAR
00:00Z00jan0000 1mn

TITLE  ures.grb  T31 grid



VARS  1

ures            
114  1,100  ures

ENDVARS

*

 



My data is three dimensionaI
and if I try to save my data in an ASCII file in MATLAB it gives a two
dimensional output. I also couldn’t solve this problem

Thank you

Deniz 

 

 



Von: gradsusr-bounces at gradsusr.org
[mailto:gradsusr-bounces at gradsusr.org]
Im Auftrag von Heiner Körnich

Gesendet: Montag, 8. November 2010 14:06

An: GrADS Users Forum

Betreff: Re: [gradsusr] netCDF control file







 

Hi
Deniz,



you don't nead a ctl-file to open a netcdf-file in grads. If your file follows
the COARDS-standard, then you can open it with 'sdfopen ures.nc'. If grads won't recognise it, you might want to
try an older grads-version. We had some problems here with grads 2.0 and
netcdf.



If grads still won't open your file, you can write a ctl-file and try to open
that with the command 'xdfopen'. The ctl-file looks a bit different from
standard ctl-files, look here:

http://www.iges.org/grads/gadoc/gradcomdxdfopen.html



Then, you would need the output from ncdump in order to know what is inside the
netcdf-file. Alternatively you can use the climate data operators (CDO) with
the command "cdo sinfo ures.nc".

Or in matlab, if you have the mexnc-package installed, you read the information
with 

info=nc_info('ures.nc')

Then you can access all details in info.



Finally, if it is only you who will use the data, it might be simpler to write
binary output in matlab and use a standard ctl.



Kind regards from Stockholm,

Heiner



On
Mon, Nov 8, 2010 at 10:11 AM, Deniz Demirhan Bari <bari at iap-kborn.de>
wrote:





Dear Grads users, 

I have calculated residual wind components
in MATLAB and saved them in netCDF file. Now I want to read them in grads but I
cannot create a netcdf control file.

I tried to get the output of ncdump but my computer doesn’t recognize ncdump although I installed it. I am using the latest version of Grads on a Suse Linux computer. My attempt to create a ctl file is below: 

*

DSET  ^ures.nc

DTYPE  netCDF

XDEF 96 LINEAR 0.000000 3.750000

YDEF 48 LEVELS -87.159 -83.479 -79.777
-76.070 -72.362 -68.652

              
-64.942 -61.232 -57.521 -53.810 -50.099 -46.389

              
-42.678 -38.967 -35.256 -31.545 -27.833 -24.122

              
-20.411 -16.700 -12.989  -9.278  -5.567  -1.856

                
1.856   5.567   9.278  12.989  16.700 
20.411

               
24.122  27.833  31.545  35.256  38.967  42.678

               
46.389  50.099  53.810  57.521  61.232  64.942

               
68.652  72.362  76.070  79.777  83.479  87.159

ZDEF 114 LINEAR 1 1

TDEF 1 LINEAR 00:00Z00jan0000 1mn

OPTIONS yrev

UNDEF  -9e+33

VARS  1

ures            
114  1,100  ures

ENDVARS

* 

Thanks in advance

Deniz DEMIRHAN BARI

Leibniz-Institut für Atmosphärenphysik e.V.

an der Universität Rostock

Schlossstraße 6

18225 Kühlungsborn

 

 







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-- 

Heiner Körnich    

Dept. of Meteorology            Tel:  +46 8
164333

Stockholms University, SE-106 91 Stockholm, Sweden

Email: heiner at misu.su.se  
www.misu.su.se/~heiner/











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-- 

Heiner Körnich    

Dept. of Meteorology            Tel:  +46 8
164333

Stockholms University, SE-106 91 Stockholm, Sweden

Email: heiner at misu.su.se   www.misu.su.se/~heiner/







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