Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
Due to the current gap in continued funding from the U.S. National Science Foundation (NSF), the NSF Unidata Program Center has temporarily paused most operations. See NSF Unidata Pause in Most Operations for details.
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 >
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