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[GEMPAK #ZTH-407575]: GEMPAK nagrib issue

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  • Subject: [GEMPAK #ZTH-407575]: GEMPAK nagrib issue
  • Date: Thu, 05 Dec 2013 12:20:32 -0700
> OK, I uploaded at the site below.

Thanks!  I just grabbed the file and ran wgrib2 on it and see it is a grib2 
file:


wgrib2 avn.2012103000f00.grib2
grib1 message ignored (use wgrib)
grib1 message ignored (use wgrib)
grib1 message ignored (use wgrib)


wgrib avn.2012103000f00.grib2 | head -5

Undefined parameter table (center 7-0 table 255), using NCEP-opn
1:0:d=12103000:UGRD:kpds5=33:kpds6=220:kpds7=0:TR=10:P1=0:P2=0:TimeU=1:planetary
 boundary layer (from Richardson no.):anl:NAve=0
...
315:30554548:d=12103000:5WAVA:kpds5=230:kpds6=100:kpds7=500:TR=10:P1=0:P2=0:TimeU=1:500
 mb:anl:NAve=0

So it is in fact a grib1 file, which is why NAGRIB worked.  

As for decoding the file, dcgrib2 is designed to decode both grib1 and grib2 
messages.  I ran dcgrib2 avn.gem < avn.2012103000f00.grib2 and now have a 32 Mb 
file with 313 grids (via GDINFO):

GEMPAK-GDINFO>l
 GDFILE   = avn.gem
 LSTALL   = YES
 OUTPUT   = T
 GDATTIM  = all
 GLEVEL   = all
 GVCORD   = all
 GFUNC    = all
 GEMPAK-GDINFO>r

 GRID FILE: avn.gem                                                             
                                

 GRID NAVIGATION: 
     PROJECTION:          CED                 
     GRID SIZE:          360 181
     LL CORNER:             -90.00      0.00
     UR CORNER:              90.00     -1.00

 GRID ANALYSIS BLOCK: 
      UNKNOWN ANALYSIS TYPE 

 Number of grids in file:   313

 Maximum number of grids in file:   5000


And with the input to GDCNTR that you sent I produce the attached image which 
shows no missing swath around the prime meridian.

Now, after this, I go back to the avn file you sent and run NAGRIB as you 
instruct.  then I plot the file test.grd with GDCNTR again and see an exact 
copy pixel by pixel of the image produce with DCGRIB2 and GDCNTR.

So again, I'm perplexed.  We seem to be doing the same thing but getting 
different results.

Michael









> Perhaps there is an issue with NAGRIB2 (if it was supposed to be used for
> decoding this file) in which case it would help to track down that error
> perhaps creating the issue.
> 
> Thanks.
> 
> John
> 

Ticket Details
===================
Ticket ID: ZTH-407575
Department: Support GEMPAK
Priority: Normal
Status: Open

Attachment: avn.gif
Description: GIF image