Sebastian,
please try using NetcdfFileWriter.addDimension to create each dimension
and add it to the target file, after testing that it does not already
exist. You can use NetcdfFileWriter.findDimension to locate dimensions
in the target file. In your code below, your new Dimension instances
have not been yet been added to the target file so cannot be used to
define variables.
Kind regards,
Ben.
On 16/02/18 03:02, Sebastian Raubach wrote:
Hello,
I've been tasked with running some data manipulation across a netcdf file. It's
supposed to work off an existing file, but create a new one that has the same
structure (although dimensions will have different lengths) and then change
some of the cell values by applying a formula.
I'm currently trying to replicate the structure of the existing file in the new
file. I can copy the global attributes just fine and wanted to re-create the
variables and dimensions next. To do so, I wrote this code:
@Override
public void process(NetcdfFile original, NetcdfFileWriter
target, Config config) throws IOException
{
for(Attribute att :
original.getGlobalAttributes())
target.addGroupAttribute(att.getGroup(), att);
for(Variable var : original.getVariables())
{
Group group =
target.addGroup(null, var.getGroup().getShortName());
List<Dimension> dimensions = new
ArrayList<>();
for(Dimension dim :
var.getDimensions())
{
dimensions.add(new Dimension(dim.getShortName(), dim.getLength(),
dim.isShared(), dim.isUnlimited(), dim.isVariableLength()));
//
dimensions.add(new Dimension(dim.getShortName(), dim));
}
target.addVariable(group,
var.getShortName(), var.getDataType(), dimensions);
}
}
I ran into several issues. The code as it stands throws this exception:
Exception in thread "main" java.lang.IllegalStateException: unknown Dimension
== time = UNLIMITED; // (53970 currently)
at
ucar.nc2.iosp.netcdf3.N3header.findDimensionIndex(N3header.java:970)
at ucar.nc2.iosp.netcdf3.N3header.writeVars(N3header.java:910)
at
ucar.nc2.iosp.netcdf3.N3header.writeHeader(N3header.java:666)
at ucar.nc2.iosp.netcdf3.N3header.create(N3header.java:602)
at ucar.nc2.iosp.netcdf3.N3iosp.create(N3iosp.java:683)
at ucar.nc2.NetcdfFileWriter.create(NetcdfFileWriter.java:804)
at jhi.netcdf.Main.main(Main.java:58)
I can't really find any information online about how to best approach this
scenario or what exactly the exception means. If anyone can give me any clues
or has experience with this kind of thing, that'd really be appreciated.
Maybe there is a more convenient way to re-create an existing file structure
(not the actual data) that I'm not aware of.
Regards,
Sebastian Raubach
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