[gradsusr] xdfopen netcdf (Jennifer Adams)

Hoop hoop at colorado.edu
Fri May 31 17:37:03 EDT 2013 

All true, however, one needn't go to this much trouble.  First of all,
the xdfopen-style data descriptor file (DDF) is only three lines long
to accomplish this templating.  Secondly, as I mentioned earlier this
week, the GrADS script "sdfopent", in the standard GrADS script library:

	http://grads.iges.org/grads/gadoc/library.html
	ftp://cola.gmu.edu/grads/scripts/sdfopent.gs

not only saves you the bother of writing any DDF, since it replicates
the old three argument syntax for doing templating on the sdfopen command,
it also gives you a working example of such a three-line DDF, as what the
script does is compose the XDFopen-style DDF and then open it for you.

Of course, when I mentioned sdfopent earlier this week, I was soundly
ignored, and I expect the same will occur this time.

-Hoop

On 05/31/13 15:20, gradsusr-request at gradsusr.org wrote:
> Date: Fri, 31 May 2013 17:20:48 -0400
> From: Jennifer Adams <jma at cola.iges.org>
> Subject: Re: [gradsusr] xdfopen netcdf
> To: GrADS Users Forum <gradsusr at gradsusr.org>
> Message-ID: <9387B97A-9537-405A-9F3B-31054B4EEB67 at cola.iges.org>
> Content-Type: text/plain; charset="windows-1252"
> 
> The data are packed. See the documentation for the UNPACK keyword
> which will need the names of the attributes that contain the
> scale factor and add offset. http://iges.org/grads/gadoc/SDFdescriptorfile.html
> --Jennifer
> 
> On May 31, 2013, at 4:13 PM, Qian, JianHua wrote:
> 
>> Jennifer,
>>
>> Thanks! I got the file opened, but the value of u wind is incorrect.
>> When I use sdfopen uwnd.1979.nc,    d uwnd,  I got:
>> ga-> sdfopen uwnd.1979.nc
>> Scanning self-describing file:  uwnd.1979.nc
>> SDF file uwnd.1979.nc is open as file 1
>> LON set to 0 360 
>> LAT set to -90 90 
>> LEV set to 1000 1000 
>> Time values set: 1979:1:1:0 1979:1:1:0 
>> E set to 1 1 
>> ga-> d uwnd
>> Contouring: -15 to 15 interval 5 
>>
>> However, when I use   open uwnd_3d_day_79_08.ctl
>> D uwnd,     I got something different:
>>
>> ga-> open uwnd_3d_day_79_08.ctl
>> Scanning description file:  uwnd_3d_day_79_08.ctl
>> Data file uwnd.%y4.nc is open as file 1
>> LON set to 0 360 
>> LAT set to -90 90 
>> LEV set to 1000 1000 
>> Time values set: 1979:1:1:0 1979:1:1:0 
>> E set to 1 1 
>> ga-> d uwnd
>> Contouring: -20500 to -17000 interval 500
>>
>> I tried to add options big_endian or little_endian,  and still got unrealistic values such as
>> Contouring: -20500 to -17000 interval 500
>>
>> The following is my ctl file:
>>
>> dset ^uwnd.%y4.nc
>> dtype netcdf
>> title 3-D NCEP-DOE uwnd 1jan1979 to 31dec2008
>> options little_endian template yrev
>> undef  -1.e+34
>> xdef  144 linear 0.0 2.5
>> ydef   73 linear -90.0 2.5
>> zdef 17 levels 1000 925 850 700 600 500 400 300 250 200 150 100 70 50 30 20 10
>> tdef  10958 linear 00z01jan1979  24hr
>> vars 1
>> uwnd      17   t,z,y,x    m/s
>> Endvars
>>
>> Could you help to check the problem?
>>
>> Thanks!
>> Joshua
>>
>> From: Jennifer Adams <jma at cola.iges.org>
>> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
>> Date: Fri, 31 May 2013 13:06:03 -0400
>> To: GrADS Users Forum <gradsusr at gradsusr.org>
>> Subject: Re: [gradsusr] xdfopen netcdf
>>
>> You can't have a negative increment. 
>> ydef 73 linear -90 2.5
>>
>> You may also need to add:
>> options yrev
>>
>> --Jennifer
>>
>> On May 31, 2013, at 1:00 PM, Qian, JianHua wrote:
>>
>>> Jennifer,
>>>
>>> I used "open", but still have problem:
>>>
>>> ga-> open uwnd_3d_day_79_08.ctl
>>> Scanning description file:  uwnd_3d_day_79_08.ctl
>>> Open Error:  Missing or invalid dimension increment value
>>>   --> The invalid description file record is: 
>>>   --> ydef   73 linear 90.0 -2.5
>>>   The data file was not opened.
>>>
>>> Thanks!
>>> Joshua
>>>
>>> From: Jennifer Adams <jma at cola.iges.org>
>>> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
>>> Date: Fri, 31 May 2013 07:35:39 -0400
>>> To: GrADS Users Forum <gradsusr at gradsusr.org>
>>> Subject: Re: [gradsusr] xdfopen netcdf
>>>
>>> You have written a full descriptor file, so use 'open' instead of 'xdfopen'. --Jennifer
>>>
>>> On May 31, 2013, at 7:05 AM, Qian, JianHua wrote:
>>>
>>>> Hui and Grads Users, thanks!    
>>>> But after I added "options template", I still got the same error message:
>>>>
>>>> ga-> xdfopen uwnd_3d_day_79_08.ctl
>>>> Scanning Descriptor File:  uwnd_3d_day_79_08.ctl
>>>> gadxdf error: Missing or invalid dimension size.
>>>>   --> The invalid description file record is: 
>>>>   --> xdef  144 linear 0.0 2.5
>>>>   The data file was not opened.
>>>>
>>>> Now my ctl file is as follows:
>>>>
>>>> dset ^uwnd.%y4.nc
>>>> dtype netcdf
>>>> title 3-D NCEP-DOE uwnd 1jan1979 to 31dec2008
>>>> options template
>>>> undef  -1.e+34
>>>> xdef  144 linear 0.0 2.5
>>>> ydef   73 linear 90.0 -2.5
>>>> zdef 17 levels 1000 925 850 700 600 500 400 300 250 200 150 100 70 50 30 20 10
>>>> tdef  10958 linear 00z01jan1979  24hr
>>>> vars 1
>>>> uwnd      17   t,z,y,x    m/s
>>>> Endvars
>>>>
>>>> I do not know what is wrong with my grads descriptor file.
>>>>
>>>> Thanks!
>>>> Joshua
>>>>
>>>> From: Hui Wang - NOAA Affiliate <hui.wang at noaa.gov>
>>>> Reply-To: GrADS Users Forum <gradsusr at gradsusr.org>
>>>> Date: Thu, 30 May 2013 23:44:24 -0400
>>>> To: GrADS Users Forum <gradsusr at gradsusr.org>
>>>> Subject: Re: [gradsusr] xdfopen netcdf
>>>>
>>>> Hi Joshua,
>>>>
>>>> I think you need to add "options template" in the ctl file.
>>>>
>>>> Good luck,
>>>> Hui
>>>>
>>>> On Thu, May 30, 2013 at 10:32 PM, Qian, JianHua <JianHua_Qian at uml.edu> wrote:
>>>> Grads Users,
>>>>
>>>> I got the following message when doing
>>>> xdfopen uwnd_3d_day_79_08.ctl
>>>>
>>>> ga-> xdfopen uwnd_3d_day_79_08.ctl
>>>> Scanning Descriptor File:  uwnd_3d_day_79_08.ctl
>>>> gadxdf error: Missing or invalid dimension size.
>>>>   --> The invalid description file record is: 
>>>>   --> xdef  144 linear 0.0 2.5
>>>>   The data file was not opened.
>>>>
>>>> The descriptor file uwnd_3d_day_79_08.ctl   is copied below:
>>>>
>>>> dset ^uwnd.%y4.nc
>>>> dtype netcdf
>>>> title 3-D NCEP-DOE uwnd 1jan1979 to 31dec2008
>>>> undef  -1.e+34
>>>> xdef  144 linear 0.0 2.5
>>>> ydef   73 linear 90.0 -2.5
>>>> zdef 17 levels 1000 925 850 700 600 500 400 300 250 200 150 100 70 50 30 20 10
>>>> tdef  10958 linear 00z01jan1979  24hr
>>>> vars 1
>>>> uwnd      17   t,z,y,x    m/s
>>>> Endvars
>>>>
>>>> The data files are in the current directory:
>>>> uwnd.1979.nc
>>>> uwnd.1980.nc
>>>> ?
>>>> When I do ncdump uwnd.1979.nc , I got:
>>>> netcdf uwnd.1979 {
>>>> dimensions:
>>>> lon = 144 ;
>>>> lat = 73 ;
>>>> level = 17 ;
>>>> time = UNLIMITED ; // (365 currently)
>>>> nbnds = 2 ;
>>>> variables:
>>>> float level(level) ;
>>>> level:units = "millibar" ;
>>>> level:actual_range = 1000.f, 10.f ;
>>>> level:long_name = "Level" ;
>>>> level:positive = "down" ;
>>>> level:GRIB_id = 100s ;
>>>> level:GRIB_name = "hPa" ;
>>>> level:axis = "z" ;
>>>> level:coordinate_defines = "point" ;
>>>> float lat(lat) ;
>>>> lat:units = "degrees_north" ;
>>>> lat:actual_range = 90.f, -90.f ;
>>>> lat:long_name = "Latitude" ;
>>>> lat:standard_name = "latitude_north" ;
>>>> lat:axis = "y" ;
>>>> lat:coordinate_defines = "point" ;
>>>> float lon(lon) ;
>>>> lon:units = "degrees_east" ;
>>>> lon:long_name = "Longitude" ;
>>>> lon:actual_range = 0.f, 357.5f ;
>>>> lon:standard_name = "longitude_east" ;
>>>> lon:axis = "x" ;
>>>> lon:coordinate_defines = "point" ;
>>>> double time(time) ;
>>>> time:units = "hours since 1800-1-1 00:00:0.0" ;
>>>> time:long_name = "Time" ;
>>>> time:actual_range = 1569072., 1577808. ;
>>>> time:delta_t = "0000-00-01 00:00:00" ;
>>>> time:standard_name = "time" ;
>>>> time:axis = "t" ;
>>>> time:coordinate_defines = "start" ;
>>>> time:avg_period = "0000-00-01 00:00:00" ;
>>>> ?
>>>> Could someone give me a clue?  
>>>>
>>>> Thanks!
>>>> Joshua
>>>>
>>>> _______________________________________________
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>>>> gradsusr at gradsusr.org
>>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>>>
>>>>
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>>>
>>> --
>>> Jennifer M. Adams
>>> IGES/COLA
>>> 4041 Powder Mill Road, Suite 302
>>> Calverton, MD 20705
>>> jma at cola.iges.org
>>> _______________________________________________
>   gradsusr mailing list gradsusr at gradsusr.org
http://gradsusr.org/mailman/listinfo/gradsusr
>>> _______________________________________________
>>> gradsusr mailing list
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>>> http://gradsusr.org/mailman/listinfo/gradsusr
>>
>> --
>> Jennifer M. Adams
>> IGES/COLA
>> 4041 Powder Mill Road, Suite 302
>> Calverton, MD 20705
>> jma at cola.iges.org
>> _______________________________________________
>  gradsusr mailing list gradsusr at gradsusr.org
http://gradsusr.org/mailman/listinfo/gradsusr
>> _______________________________________________
>> gradsusr mailing list
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>> http://gradsusr.org/mailman/listinfo/gradsusr
> 
> --
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705
> jma at cola.iges.org
> _______________________________________________
> gradsusr mailing list
> gradsusr at gradsusr.org
> http://gradsusr.org/mailman/listinfo/gradsusr

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