Re: [netcdf-java] Join two files

• To: "andreas.lieta" <andreas.lieta@xxxxxxxxxxxxxx>
• Subject: Re: [netcdf-java] Join two files
• From: John Caron <jcaron1129@xxxxxxxxx>
• Date: Wed, 22 Jun 2022 11:22:47 -0600

Hi Andreas:

The write utilities aren't that convenient to use. Youll have to add the
new Variables yourself, then read data from the original file and write to
the new file.

1. What version of the library are you using?
2. Generally when you get an Exception, its best to post the complete stack
trace if you have it.
3.  I find using the GitHub issues on the appropriate repo is better than
the mailing list. YMMV.

John

On Wed, Jun 22, 2022 at 10:31 AM andreas.lieta via netcdf-java <
netcdf-java@xxxxxxxxxxxxxxxx> wrote:

> I have two Netcdf-4 files. Both are for the same region and same time
> interval. The first contains two variables U and V. The second variables S
> and T. I need to generate third Netcdf-4 file with four variables U, V, S,
> T. I had an idea to make copy of the first file and add additional
> variables to the copy. What i did:
>
>
>    1. NetcdfFile fileUV = NetcdfFiles.open(fnameUV);   // file with U and
>    V
>    2. NetcdfFile fileST = NetcdfFiles.open(fnameST);    // file with S
>    and T
>    3. Nc4Chunking chunker = Nc4ChunkingStrategy.factory(type,
>    deflateLevel, shuffle);
>    4. NetcdfFormatWriter.Builder builder =
>            NetcdfFormatWriter.createNewNetcdf4(NetcdfFileFormat.NETCDF4,
>    outName, chunker);
>    5. NetcdfCopier copier = NetcdfCopier.create(fileUV, builder);
>        // copier UV-file -> outfile
>    6. NetcdfFile ncfileOut = copier.write(null);          // do copy
>    7. NetcdfFormatWriter writer = builder.build();
>    8. ImmutableList<Variable> vST = fileST.getVariables();   // variables
>    S and T
>    9. for(var v : vST) writer.write(v, null);      // add vriables to
>    outfile
>
>
> String 7 generates the exception *java.lang.IllegalStateException: Group
> was already built.*
>
> May be it is impossible to use the same builder for copying and adding
> variables? Could anyone help me to solve my task correctly? Thanks in
> advance
>
> Andreas Lieta
>
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• References:
  • [netcdf-java] Join two files
    • From: andreas.lieta