[gradsusr] xdfopen netcdf (Jennifer Adams)
Qian, JianHua
JianHua_Qian at uml.edu
Fri May 31 23:45:25 EDT 2013
Dear Hoop,
Sorry that I ignored your early email about sdfopent.
I do not know how to build a 3-line DDF.
My data is the daily u-winds of the NCEP reanalysis:
uwnd.1979.nc (365 days)
uwnd.1980.nc (366 days, leap year)
uwnd.1981.nc (365 days)
Š
uwnd.2008.nc (366 days, leap year)
How to build the xdfopen-style data descriptor file (DDF) for these
datasets.
Please correct my following is my draft:
dset uwnd.%y4.nc
templ template
ntimes 10958 (note: this is the total number of days from 1979
to 2008)
Thanks!
Joshua
On 5/31/13 5:37 PM, "Hoop" <hoop at colorado.edu> wrote:
>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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>>>>>
>>>>>
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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
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>>>> _______________________________________________
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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
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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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