[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: Grib or GEMPAK navigation probem?

This archive contains answers to questions sent to Unidata support through mid-2025. Note that the archive is no longer being updated. We provide the archive for reference; many of the answers presented here remain technically correct, even if somewhat outdated. For the most up-to-date information on the use of NSF Unidata software and data services, please consult the Software Documentation first.

  • Subject: Re: Grib or GEMPAK navigation probem?
  • Date: 17 Feb 2006 12:45:36 -0700
Bob,

The Lo1 longitude is 59.503, while the Lov is 52.550, so the
central longitude is outside the grid domain which is not
a possibility I checked when I put in a work around for
another problem.

Here the problem with dcgrib2 is a check in the lambert grib routine
which is necessary when grids straddle the date line (eg Lo1 might be
175, but Lov -179), where if Lov is less than Lo1, it assumes that 360
has to be added so the computation is possible. This is something I put
in, and not in NCEP's distribution. I can change
$GEMPAK/source/gemlib/gb/gblamb.c to
only do that when the Lo1 > 0 and loncnt < 0.

I made that change and now the gdinfo produces:
GRID FILE:
2006011306_testme.gem                                                           
                    

 GRID NAVIGATION: 
     PROJECTION:          LCC                 
     ANGLES:                60.0    52.5    30.0
     GRID SIZE:          252 252
     LL CORNER:              29.07     59.50
     UR CORNER:              38.22     75.59

This is pakistan.

Do you want the updated routine, or a recpiled dcgrib2 binary?

Steve





On Fri, 2006-02-17 at 10:48, Robert Rozumalski wrote:
> Steve,
> 
> Attached is a grib I pulled from a larger file generated by the AFWA WFR 
> model.
> The domain should be over Afghanistan but after converting it to GEMPAK with
> dcgrib2 the domain appears to be over Hawaii. So, can you tell if the problem
> is with the navigation in gempak or the grib file?
> 
> 
> Bob
> 
> 
>