[gradsusr] Problem extracting HIRLAM gribfile

[Jennifer Adams]

On Mar 15, 2011, at 10:05 AM, Jonas Kaufmann wrote:

> Hello Wesley,
>
> thank you for your help! I could convert the file to grib2 using ECMWF
> grib_set, see the converted file as an attachment. I then used the
> latest versions of g2ctl and wgrib2 to create a control file (also
> attached). During this process I get the following error):
> Argument "0.000000:winds(grid)" isn't numeric in multiplication (*) at
> /usr/share/perl/5.10/Math/Trig.pm line 87.
>
> Now when I try to create an index file for the grib2-file, gribmap
> complains with this error:
> Open Error:  Missing or invalid dimension increment value
>  --> The invalid description file record is:
>  --> xdef 351 linear 245.437796901893 -0.459621342512909
>  The data file was not opened.

Not sure what the 1st problem mentioned above means, but this message  
is telling you that XDEF cannot have a negative increment value. You  
must start with the minimum longitude and have positive increment.
--Jennifer

>
> Is there a simple (manual?) way to fix this in the control file? Or is
> there another option on how to display data from this file?
>
> Thank you for your help!
>
>
> Best regards,
> Jonas Kaufmann
>
> On Fri, Mar 11, 2011 at 20:08, Wesley Ebisuzaki
> <Wesley.Ebisuzaki at noaa.gov> wrote:
>> Jonas,
>>
>>   Your grib1 file is packed using "complex packing".  This kind of
>> packing is
>> not supported by grib2ctl and GrADS.
>>
>>   I think that you are getting the error message because the grid is
>> (582 x 424) or 246768 points.
>> However, the number of grid points (could be modified by undefineds  
>> and
>> runs of identical values)
>> is given by octets 19-20 in section 4. Since 246768 much too big to  
>> be
>> stored in a 2 byte number,
>> an error is flagged.  Try converting this file to grib2 using the  
>> ECMWF
>> software.  Once in grib2,
>> g2ctl and GrADS can read it.  I don't think that g2ctl will handle  
>> the
>> projection right but at least you
>> can display it as a x-y grid.
>>
>>> http://www.nco.ncep.noaa.gov/pmb/docs/on388/section4.html
>>
>>
>>    Wesley Ebisuzaki
>>
>> Jonas Kaufmann wrote:
>>> Hello,
>>>
>>> I ran into a problem trying to extract a HIRLAM data set on a  
>>> rotated
>>> lat-lon grid. the file is in grib1-format. I could create a valid
>>> control file using the code from g2ctl.pl for grib2-files, merging
>>> this together with the code in grib2ctl.pl for grib1 files.  
>>> Although a
>>> control file is created, I also get errors like:
>>>
>>> grib header at record 1: two values of nxny 246768 144639
>>>    LEN 162734 DataStart 14 UnusedBits 6 #Bits 9 nxny 246768
>>>
>>> When I then go ahead and try to plot a map using GrADS, I always get
>>> "Entire Grid undefined". I have attached the grib file, the index  
>>> file
>>> and the control file.
>>>
>>> What am I doing wrong? How can I extract the data from this  
>>> gribfile?
>>>
>>> Thank you for your help!
>>>
>>> Best regards,
>>> Jonas Kaufmann
>>> ------------------------------------------------------------------------
>>>
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>>> gradsusr at gradsusr.org
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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



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