[netCDF #HOT-122007]: converting grib2 files to netcdf using wgrib2 -netcdf

John,

You responded:
> New Staff Reply: converting grib2 files to netcdf using wgrib2 -netcdf
> 
> Im not sure what you mean by a "Grib2 file". Everything inside the CDM librar
> y uses the NetcdfFile abstraction.
> 
> > Dear Unidata:
> > 
> > Thanks for the help.  When I wrap the original dataset in ncml, can the
> > original dataset be a Grib2 file or must it be NetCDF?

I think the answer to his question may be just "Yes", because he was
converting Grib2 files to netCDF using:

 java -Xmx512m -classpath netcdfAll-4.0.jar ucar.nc2.dataset.NetcdfDataset -in 
myfile.grib2 -out out.nc

so now he wants to know if he can just create an ncml wrapper for
myfile.grib2 and instead use:

 java -Xmx512m -classpath netcdfAll-4.0.jar ucar.nc2.dataset.NetcdfDataset -in 
myfile.ncml -out out.nc

I think you had previously indicated he could use the <remove> element
of ncml, so maybe he's asking about a grib2 file that contains a
collection of grib2 objects appended together, and does the <remove>
element still work in this case to remove some of them from the
resulting output netCDF file ...

--Russ

> > Thanks,
> > 
> > Larry Mastin
> > 
> > David A. Johnston Cascades Volcano Observatory
> > 1300 SE Cardinal Court, Bldg. 10, Suite 100
> > Vancouver, WA 98683 USA
> > tel. 360-993-8925  fax 360-993-8980
> > http://vulcan.wr.usgs.gov/Projects/Mastin
> > -----Original Message-----
> > From: Unidata netCDF Java Support
> > [mailto:address@hidden]
> > Sent: Friday, November 06, 2009 2:59 PM
> > To: address@hidden
> > Cc: address@hidden
> > Subject: [netCDF #HOT-122007]: converting grib2 files to netcdf using wgrib
> 2
> > -netcdf
> > 
> > The -isLargeFile option is now in the lastest 4.1 release at:
> > 
> > http://www.unidata.ucar.edu/software/netcdf-java/
> > 
> > under the "Development version 4.1" downloads.
> > 
> > You can wrap the original dataset in ncml, and use the <remove> element to
> > remove the ones you dont want, see
> > 
> > http://www.unidata.ucar.edu/software/netcdf/ncml/
> > 
> > example at:
> > 
> > http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Cookbook.html#remove
> > 
> > the xml file must have the suffix ".ncml", and it then becomes the "in"
> > file:
> > 
> > java -Xmx512m -classpath netcdfAll-4.0.jar ucar.nc2.dataset.NetcdfDataset
> > -in myfile.ncml -out out.nc
> > 
> > > Russ:
> > >
> > > Thanks again for the quick response.  Actually, I only need the wind fiel
> d
> > > data (UGRD, VVEL, AND VGRD), and only for a particular geographic
> > subregion.
> > > If there's a way to just convert those data to NetCDF, the -isLargeFile
> > > option won't be necessary.
> > >
> > > I'm just learning how to do this.  I'll poke through the NetCDF-Java
> > > documentation.  If you know offhand how it would be done and can tell me,
> > > that would be even better.
> > >
> > > Thanks again,
> > >
> > > Larry
> > >
> > > David A. Johnston Cascades Volcano Observatory
> > > 1300 SE Cardinal Court, Bldg. 10, Suite 100
> > > Vancouver, WA 98683 USA
> > > tel. 360-993-8925  fax 360-993-8980
> > > http://vulcan.wr.usgs.gov/Projects/Mastin
> > > -----Original Message-----
> > > From: Unidata netCDF Java Support
> > > [mailto:address@hidden]
> > > Sent: Thursday, November 05, 2009 4:41 PM
> > > To: address@hidden
> > > Cc: address@hidden
> > > Subject: [netCDF #HOT-122007]: converting grib2 files to netcdf using
> > wgrib2
> > > -netcdf
> > >
> > > Hi Larry:
> > >
> > > The problem is that the 2 Gb netcdf file limit is being exceeded (yes it
> > > expands that much!). I will add a -isLargeFile option to allow writing to
> > > the 64-bit offset version. It will take a few days to get teh release out
> ,
> > > ill let you know when its ready.
> > >
> > > > Thanks, Russ.
> > > >
> > > > I downloaded NetCDFAll-4.0.jar from that site and it now finds the main
> > > > class.  However I am getting another error message indicating the
> > > > variable starting position is exceeding an allowed value (see below).
> > > >
> > > > My grib2 file is pretty big (383 Mb).  Is there a size limit to the
> > > > grib2 files that can be read?
> > > >
> > > > Thanks,
> > > >
> > > > Larry
> > > >
> > > > *******************************************************************
> > > > Command & error messages below:
> > > >
> > > > lgmastin@phobos:~/ncj> java -Xmx512m -classpath netcdfAll-4.0.jar
> > > > ucar.nc2.dataset.NetcdfDataset -in
> > > > ~/grib2/testfiles/NAM_Alaska_11km_20090920_0600.grib2 -out
> > > > ~/grib2/testfiles/NAM_Alaska_11km_20090920_0600.nc
> > > > Read
> > > > from /home/lgmastin/grib2/testfiles/NAM_Alaska_11km_20090920_0600.grib2
> > > > write to /home/lgmastin/grib2/testfiles/NAM_Alaska_11km_20090920_0600.n
> c
> > > >
> > > > Exception in thread "main" java.lang.IllegalArgumentException: Variable
> > > > starting pos=2343709348 may not exceed 2147483647
> > > > at ucar.nc2.iosp.netcdf3.N3header.writeHeader(N3header.java:626)
> > > > at ucar.nc2.iosp.netcdf3.N3header.create(N3header.java:560)
> > > > at ucar.nc2.iosp.netcdf3.N3iosp.create(N3iosp.java:640)
> > > > at ucar.nc2.NetcdfFileWriteable.create(NetcdfFileWriteable.java:594)
> > > > at ucar.nc2.FileWriter.writeToFile(FileWriter.java:195)
> > > > at ucar.nc2.dataset.NetcdfDataset.main(NetcdfDataset.java:1600)
> > > >
> > > >
> > > > On Thu, 2009-11-05 at 16:11 -0700, Unidata netCDF Java Support wrote:
> > > > > Larry,
> > > > >
> > > > > Alternatively, if from
> > http://www.unidata.ucar.edu/software/netcdf-java/
> > > > > you had downloaded
> > > > >
> > > > >   "The complete netCDF library (MD5) implements the full CDM model,
> > with
> > > all dependent jars included."
> > > > >
> > > > > you would have gotten  netcdfAll-4.0.jar file instead of the .zip fil
> e
> > > you used, and that would have worked, using:
> > > > >
> > > > >   java -Xmx512m -classpath netcdfAll-4.0.jar
> > > ucar.nc2.dataset.NetcdfDataset -in
> > > ~/grib2/testfiles/NAM_Alaska_11km_20090920_0600.grib2 -out
> > > > > ~/grib2/testfiles/NAM_Alaska_11km_20090920_0600.nc
> > > > >
> > > > > --Russ
> > > > >
> > > > >
> > > > > Russ Rew                                         UCAR Unidata Program
> > > > > address@hidden                     http://www.unidata.ucar.edu
> > > > >
> > > > >
> > > > >
> > > > > Ticket Details
> > > > > ===================
> > > > > Ticket ID: HOT-122007
> > > > > Department: Support netCDF Java
> > > > > Priority: Normal
> > > > > Status: Closed
> > > > >
> > > >
> > > >
> > >
> > >
> > > Ticket Details
> > > ===================
> > > Ticket ID: HOT-122007
> > > Department: Support netCDF Java
> > > Priority: Normal
> > > Status: Open
> > >
> > >
> > >
> > >
> > 
> > 
> > Ticket Details
> > ===================
> > Ticket ID: HOT-122007
> > Department: Support netCDF Java
> > Priority: Normal
> > Status: Closed
> > 
> > 
> > 
> > 
> 
> 
> Ticket Details
> ===================
> Ticket ID: HOT-122007
> Department: Support netCDF Java
> Priority: Normal
> Status: Closed
> Link:  https://www.unidata.ucar.edu/esupport/staff/index.php?_m=tickets&_a=vi
> ewticket&ticketid=10101



Ticket Details
===================
Ticket ID: HOT-122007
Department: Support netCDF Java
Priority: Normal
Status: Closed