[gradsusr] xdfopen netcdf

Jennifer Adams jma at cola.iges.org
Fri May 31 17:20:48 EDT 2013


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
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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
> _______________________________________________
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--
Jennifer M. Adams
IGES/COLA
4041 Powder Mill Road, Suite 302
Calverton, MD 20705
jma at cola.iges.org



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