Meteogram error

Fil fil at METEOPT.COM
Sat Sep 6 09:26:05 EDT 2008


Hi. With the latest beta the error I had is gone but as you said drawing one
meteogram takes forever, like 10 minutes or so. Is it possible you could
post your solution?

Best regards.

2008/3/3 Jennifer Adams <jma at cola.iges.org>

> Drawing meteograms with grib2 data highlights the principal drawback of the
> compressed data format -- you must read and uncompress a global grid in
> order to extract data values at a single grid point. The time series plots
> and especially the Z-T panel at the top of the meteogram require a
> significant amount of memory and I/O when using grib2 data. My experience is
> that even on local data files, it can take 10+ minutes to draw a meteogram.
> When using data that is behind GDS ... I'm not sure whether the request
> would timeout before the I/O was finished. Haven't tried it.
> My workaround for drawing the meteograms at wxmaps.org was to use fwrite
> to extract the required data first, then draw the meteograms based on the
> fwritten data set. There were other issues too that were solved with fwrite
> scripts: the precip fields are 3hr accumulations at 3hr forecast intervals
> and 6hr accumulations at 6hr forecast intervals. I will try to post a
> generalized script solution to the grib2 meteogram problem as soon as I
> can.
>
> The other problem you have is unrelated to the above. I believe the "Unable
> to open file" error message might come from a missing null terminator at the
> end of the string variable that contains the data set name. (The behavior of
> strncpy() does not seem to be the same on all systems.) This was a bug that
> was reported by Hoop after he tried out the 2.0.a1 builds. The patch is a
> one-line bit of code that will be in 2.0.a2 (coming out very soon). If you
> are using a pre-compiled binary downloaded from COLA, I suggest you try
> downloading a fresh copy -- Hoop's builds of 2.0.a1 for 32-bit linux (that
> are posted on COLA's FTP server) contain the fix, but they were re-posted a
> few days after the release of 2.0.a1.
>
> Jennifer
>
> On Mar 1, 2008, at 12:53 PM, Fil wrote:
>
> Hi all,
>
> I'm trying to use the meteogram scripts available at IGES ftp server but I
> always get the following error:
>
> ga-> meteogram_gfsb Boston 2008030112 -71 42 e
> No hardcopy metafile open
> All files closed; all defined objects released;
> All GrADS attributes have been reinitialized
> NetCDF Error (nc_open): Unable to open file
> http://monsoondata.org:9090/dods/gfs2/gfs.2008030112b
> read_metadata: gaopnc failed
> gadsdf: Couldn't ingest SDF metadata.
>
> I'm using gradsdap 2.0.a1 on i686 32b Linux system. Anyone knows what the
> problem is?
>
> Regards.
>
>
> --
> Jennifer M. Adams
> IGES/COLA
> 4041 Powder Mill Road, Suite 302
> Calverton, MD 20705
> jma at cola.iges.org
>
>
>
>
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