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NOTICE: This version of the NSF Unidata web site (archive.unidata.ucar.edu) is no longer being updated.
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Hi John, Thanks for this - I could generate the coordinates in NcML but the problem is that every day a new file gets added in to the timeseries and I don't want to have to edit the NcML every day. This is why I wanted to do it with a <scan>. Furthermore, missing data files are possible so we can't assume that the files we have are equally spaced in time. I think this would be a good enhancement. It might be hard to send you the data files because they are (a) big and (b) commercial in nature, but I might be able to sort something out. It's probably not too hard to create some dummy datasets though? Cheers, Jon On 2/9/07, John Caron <caron@xxxxxxxxxxxxxxxx> wrote:
Hi Jon: At the moment, all you can do is generate the coordinates yourself in the NcML, following this section of the docs: http://www.unidata.ucar.edu/software/netcdf/ncml/v2.2/Aggregation.html#JoinExistingTypes Otherwise we'll have to add a "request for enhancement" on dealing with join coordinates whose units change. It would be helpful to have some datasets with this problem for testing. Regards, John Jon Blower wrote: > Dear all, > > I've come across a problem when aggregating a dataset across the time > dimension using NcML and the latest (2.2.18) nj22 library. I would > like to aggregate a number of files, which represent timesteps of an > ocean forecast model (one timestep per file). I am aggregating using > an NcML file like this: > > <netcdf xmlns="http://www.unidata.ucar.edu/namespaces/netcdf/ncml-2.2";> > <aggregation dimName="t" type="joinExisting"> > <scan location="/path/to/files" suffix=".nc"/> > </aggregation> > </netcdf> > > When reading this NcML file using NetcdfDataset.openDataset() I get an > aggregated dataset with the correct number of timesteps BUT all the > values along the time axis are the same. > > After much head-scratching I think I've found the source of the > problem, but I don't have a solution. In each individual file, the > time dimension is specified with different units but the values remain > the same: > > File 1: time units: seconds since 2007-02-06 00:00:00, value: 43200 > File 2: time units: seconds since 2007-02-07 00:00:00, value: 43200 > > This seems to confuse the aggregation code, which I assume expects the > units to remain constant between files and the values to change. > > Is there a solution or workaround for this? I don't control how the > netCDF files are made so I don't think I can change them. Any help > will be much appreciated. > > Regards, Jon >
-- -------------------------------------------------------------- Dr Jon Blower Tel: +44 118 378 5213 (direct line) Technical Director Tel: +44 118 378 8741 (ESSC) Reading e-Science Centre Fax: +44 118 378 6413 ESSC Email: jdb@xxxxxxxxxxxxxxxxxxxx University of Reading 3 Earley Gate Reading RG6 6AL, UK -------------------------------------------------------------- ============================================================================== To unsubscribe netcdf-java, visit: http://www.unidata.ucar.edu/mailing-list-delete-form.html ==============================================================================
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