Re: 20031003: gribtocdl not writing data

• To: Lori Thompson <Lori.Thompson@xxxxxxxx>
• Subject: Re: 20031003: gribtocdl not writing data
• From: Robb Kambic <rkambic@xxxxxxxxxxxxxxxx>
• Date: Fri, 3 Oct 2003 10:00:08 -0600 (MDT)

On Fri, 3 Oct 2003, Lori Thompson wrote:

So the cdl file only contains information on the coordinates and not
the data for the variables?

Lori,

That's correct, cdl are only template files for the netCDF files.


I have done ascii to NetCDF conversions

where the cdl file takes the form:

data:
lev = ;
lon = ;
lat = ;
var1 = ;
var2 = ;
.
.
.
varn = ;
}

So are you saying that gribtocdl will create a cdl file with only:
data:
lev = ;
lon = ;
lat = ;
}

I used gribtonc following gribtocdl and received the error message:
ncgen: isabel13l.2003091100.grib3rd.f00.cdl line 258: too many values for
this variable, 225 >= 225

This is referring to the lon points which have 226. The same is true for
lat. I manually removed the extra lon/lat points and reran gribtonc and
received a segmentation fault. I did this for 225 and 224 point.

I hate to say this but gribtocdl isn't perfect becasue there are so many
variations of GRIB files, it's used as a starting point as you found out.
Deleting the extra lat/lon points etc was the correct thing to do.

If you send me the cdl file and a grib product, I'll take a look at it.
Also what version of the decoders package are you using?  One version did
do segmentation fault on some GRIB products but I thought it was fixed.
This could be a good test case for me.

Robb...

Thanks,
Lori


I did have a misunderstanding of gribtocdl. I thought the cdl
file was supposed to contain

On Fri, 3 Oct 2003, Robb Kambic wrote:

> On Fri, 3 Oct 2003, Unidata Support wrote:
>
> >
> > ------- Forwarded Message
> >
> > >To: support-decoders@xxxxxxxxxxxxxxxx
> > >From: Lori Thompson <Lori.Thompson@xxxxxxxx>
> > >Subject: gribtocdl not writing data
> > >Organization: NOAA
> > >Keywords: 200310031240.h93CeHk1011045 gribtonc gribtocdl
> >
> > Hello. I'm using gribtocdl and gribtonc to convert grib files to NetCDF.
> > The grib data files have 7 variables, 5 of which have a vertical
> > structure. gribtocdl creates the cdl file and returns the message:
> >
> > Oct 03 12:38:02 gribtocdl[10036]: Starting Up
> > Oct 03 12:38:04 gribtocdl[10036]: EOF on input
> > Oct 03 12:38:04 gribtocdl[10036]: Exiting
> > Oct 03 12:38:04 gribtocdl[10036]: 111 WMO msgs, 111 GRIBs decoded, 111
> > written
> >
> > which contains the correct number 111. The cdl file writes out the lat/lon
> > and time data correctly and has the correct metadata for the variables.
> > However, the cdl file does not write out any data for the variables and
> > ends with lat data.
>
> Lori,
>
> I think you have a slight misunderstanding, gribtocdl just creates cdl
> files with only data of the projection/lat/lon/etc.  To actually create a
> netCDF file one has to use gribtonc with the cdl created by gribtocdl. ie
>
> % gribtonc -l - your.cdl your.nc < your.gribdata
>
> This will create a your.nc netCDF file. gribtonc also needs the ncgen
> utility to create the template your.nc from the your.cdl. ncgen is
> included in the netCDF package.  I wasn't quite sure of your question, let
> me know if I misinterpreted it.
>
> Robb...
>
> >
> > I am running the utility on a Linux machine.
> >
> > Any suggestions on why this is occuring?
> >
> > Thanks,
> > Lori
> >
> >
> >
> > ------- End of Forwarded Message
> >
> >
--
----------------------------------------------------
Lori A. Thompson
Applications Programmer/RS Information Systems, Inc.
Geophysical Fluid Dynamics Laboratory/NOAA
Princeton University Forrestal Campus/Route 1
PO Box 308
Princeton, NJ 08542
Phone: 609-452-6563
Fax:   609-987-5063
http://www.gfdl.noaa.gov/~lat

==============================================================================
Robb Kambic                                Unidata Program Center
Software Engineer III                      Univ. Corp for Atmospheric Research
rkambic@xxxxxxxxxxxxxxxx                   WWW: http://www.unidata.ucar.edu/
==============================================================================