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[GEMPAK #HAT-279589]: Decoding GRIB to GEMPAK

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  • Subject: [GEMPAK #HAT-279589]: Decoding GRIB to GEMPAK
  • Date: Thu, 05 Oct 2006 16:26:17 -0600
Quang,

Your dcgrib2 error log message provides the answer:
[17780] 060925/1455[DCGRIB -55] Grid too large 1440 x 720 [1036800 > 750000]

Your grid is 1036800 points, whereas the maximum grid that can be stored is
defined at compile time as 750,000 points.

However, you must be using an older distribution. The LLMXTG I configured
in the 5.9.3 distribution is 1,679,940 points.

GEMPAK has 2 parameters, LLMXTG which is the larges grid that can be stored,
and LLMXGD which is the maximum number of gridpoints that can be used in
grid calculations. The LLMXGD setting in 5.9.3 is 400,000. The IJSKIP
parameter allows a grid to be subsampled, or the GAREA can be set to a subarea.

LMXTG and LLMXGD can be edited in the source distribution in 
$GEMPAK/include/MCHPRM.*
and gemprm.h.

Steve Chiswell
Unidata User Support



> Dear Dr. Steve,
> 
> My question today is related to the problem of
> transfering a GRIB1 file into GEMPAK's format (*.gem)
> 
> I'll show you the output of using dcgrib2.
> First, to check the GRIB1 file is Ok, I used wgrib -V
> filename and the output is
> rec 1:0:date 2006092116 WIND kpds5=32 kpds6=0 kpds7=0
> levels=(0,0) grid=255 anl:
> WIND=Wind speed [m/s]
> timerange 10 P1 0 P2 0 TimeU 1 nx 1440 ny 720 GDS
> grid 0 num_in_ave 0 missing 0
> center 100 subcenter 0 process 255 Table 3
> latlon: lat 0.000000 to 90.000000 by 0.250000 nxny
> 1036800
> long 0.000000 to 360.000000 by 0.250000,
> (1440 x 720) scan 21 mode 1 bdsgrid 1
> min/max data 0 655.344 num bits 16 BDS_Ref 0
> DecScale 0 BinScale -6
> Second, I used dcgrib2. The result is it creats files
> dcgrib2.log, gemglb.nts and last.nts but not a gem
> file.
> 
> So how can I do now?
> Many thanks from you.
> Quang
> 
> Nguyen Dang Quang
> Dept. of Research and Application
> Vietnam National Center for Hydrometeorological Forecast
> 4 Dang Thai Than, Hanoi, VIETNAM
> Tel.:84-4-9330942


Ticket Details
===================
Ticket ID: HAT-279589
Department: Support GEMPAK
Priority: Low
Status: Closed