Ross,
Bob is right. There is no an out-of-the-box routine/method in
NetCDF-Java to do this for you.
If you try to code this yourself in Java, you'll get to deal with a
lot of tricky details related to diverse conventions (CF, ...).
AFAIK, none of the NCO operators produces multiple output files, i.e.
you cannot give an nco tool a single input file and get multiple
output files (split a NetCDF file by time axis into multiple files).
However, CDO is able to do this:
https://code.zmaw.de/projects/cdo/embedded/index.html#x1-1070002.2.8
You may use "Process" as Bob suggests or a more powerful lib, e.g.
wrapper around native Java "Process":
https://github.com/zeroturnaround/zt-exec to invoke CDO from Java.
The final notice: CDO is much limited compared to NCO regarding
support of generic NetCDF files. This means that if your NetCDF files
contain axes other than latitude, longitude, level, time (see the
manual for the detailed list) - CDO will refuse to handle such files.
2017-04-02 21:05 GMT+03:00 Bob Simons - NOAA Federal <bob.simons@xxxxxxxx>:
> Two ways you can do this:
>
> 1) If you can do something in NCO, it is probably much simpler to keep doing
> it in NCO. From Java, you can call
> Process process = Runtime.getRuntime().exec(cmd);
> to call an operating system process (but see the detailed examples on the
> web for how to do this for your operating system), including calling NCO.
>
> 2) If I understand the problem, the only way I know of to do this with
> netcdf-java, is to read the time and other data values and write the .nc
> files with the individual time values and the data associated with each time
> (and all the associated dimensions and attributes). That's the nature of
> working with netcdf-java. (Perhaps someone else will chime in with a simpler
> method.)
>
> P.S. I don't know your reasons for using netcdf-java 4.2. I understand that
> sometimes projects are, for now, locked into a certain version. But if you
> can, I encourage you to switch to the latest version (4.6.8). Things are
> done differently in recent versions of netcdf-java and various bugs have
> been fixed. You'll probably have to switch to a modern version of Java
> someday, so, if you can, you might as well switch now so you don't have to
> rewrite this code later.
>
>
>
>
> On Sun, Apr 2, 2017 at 6:19 AM, Alter, Ross E ERDC-RDE-CRREL-NH CIV
> <Ross.E.Alter@xxxxxxxxxxxxx> wrote:
>>
>> Hi all,
>>
>> I'm using the Java Netcdf API (v4.2) to work with weather model output in
>> Netcdf format. However, I am trying to convert a NetcdfFile with multiple
>> time steps to a List of NetcdfFiles with single time steps, and I can't seem
>> to find a direct way to accomplish this using the existing NetcdfFile
>> methods without first reading a specific variable (which I would prefer not
>> to do). I'm aware of how to solve this using NCO, but I would like to solve
>> this using Java since that is the language in which the software is written.
>> If you could please offer a suggestion on the most effective way to
>> accomplish the above, I'd really appreciate it.
>>
>> Thanks a lot for your help!
>>
>> Ross
>>
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>
>
>
>
> --
> Sincerely,
>
> Bob Simons
> IT Specialist
> Environmental Research Division
> NOAA Southwest Fisheries Science Center
> 99 Pacific St., Suite 255A (New!)
> Monterey, CA 93940 (New!)
> Phone: (831)333-9878 (New!)
> Fax: (831)648-8440
> Email: bob.simons@xxxxxxxx
>
> The contents of this message are mine personally and
> do not necessarily reflect any position of the
> Government or the National Oceanic and Atmospheric Administration.
> <>< <>< <>< <>< <>< <>< <>< <>< <><
>
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