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20030102: DCGRIB vs. NAGRIB for WSETA (fwd)


Brett,

If using dcgrib, you should specify the "PACK" command line
option, otherwise, you are using unpacked GEMPAK grid files
(which would be faster for reading).

But, you really should used dcgrib2 which uses the grib
packing without unpacking first, is much faster, and
will support file naming templates.

The use of dcgrib/dcgrib2 is for decoding from a stream
(of LDM pipe action if you send the data via LDM as grib).
Nagrib can only decode from a file on disk.

Steve Chiswell


> ---------- Forwarded message ----------
> Date: Thu, 02 Jan 2003 15:25:57 -0700
> From: Brett Mcdonald <address@hidden>
> To: address@hidden
> Subject: DCGRIB vs. NAGRIB for WSETA
>
> Bob,
>
> I just got my LINUX machine rebuilt and got the workstation ETA running
> the other day.  Made some tweaks to the parameters today and checked out
> the output.  I am using the strc binaries for the 75x121 grid size.
> Everything has gone fairly well in setting it up.
>
> Anyhow, the decoded GEMPAK file for today's 12z run came out to be 397
> MB - pretty darn big for a 149z121 grid size going out to 36 hours with
> output every 3 hours.
>
> So, I then used nagrib_nc to decode the GRIB files instead of dcgrib.
> The resultant file size was 123 MB -> more that 3 times smaller!
>
> What's the rationale then behind using dcgrib vs. nagrib, especially
> with the file size difference?  Any idea what is causing the file size
> difference?
>
> Thanks
>
> Brett
>