[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[netCDFJava #SBB-665470]: xml to netcdf



Hi Ghansham,

In NcML, you can use the <values> tag inside a variable to set the values. If
you want to point the NcML to an external dataset, you will need to write an
IOSP to enable netCDF-Java to read the file.

netCDF has a utility called ncgen, which creates a netCDF file from a CDL file:


http://www.unidata.ucar.edu/software/netcdf/docs/ncgen-man-1.html

CDL files are not xml, but they are simple none-the-less:

http://www.unidata.ucar.edu/software/netcdf/docs/ncgen-man-1.html#EXAMPLES

You would still need to write a program to read in your ascii or binary data to 
write
the CDL file, but at that point you might as well just write out a netCDF 
object using
the netCDF C or Java API.

Sean

PS: Rosetta is a very new project that is still in active development. It can 
currently
convert ASCII data from station baseed sites into  CF 1.6 compliant netCDF 
files, but
this is certainly only the first step for the project.

> Can you put up a sample program along with dataset. Here are a few things
> to consider. NcML always refers to a dataset. Can it refer to binary data
> on disk and read it to create a variable within the file. I hope I am not
> confusing you. I have set of binary and ascii files which I want to write
> into netcdf-4 using ncml. I am afraid if that is possible. Rosetta is
> trying to do it for CSV files. I will send you a sample xml file what I
> take as input to write hdf-5 file.
> 
> Long time back hdf5 used to have a utility called h5gen which used to take
> xml input to generate hdf5. But they have discontinued it. God knows  the
> reason. They are switching from XML to JSON based approach as that is too
> portable and very hot topic as far as web is concerned.
> FYI, JSON  has a new incarnation for binary data in the form BSON (binary
> JSON). http://bsonspec.org/
> 
> 
> 
> 
> regards
> Ghansham
> 
> 
> address@hidden> wrote:
> 
> > Greetings Ghansham,
> >
> > Yes, you can convert NcML to a netCDF file using netCDF-Java. See
> >
> > http://www.unidata.ucar.edu/software/netcdf/ncml/
> >
> > for more details (look for "Using NcML to create a NetCDF-3 file").
> > The link above uses ucar.nc2.FileWriter, which is deprecated, but
> > should still work if you are looking for something quick.
> >
> > That said, I would recommend using
> >
> > ucar.nc2.FileWriter2
> >
> > (
> > www.unidata.ucar.edu/software/netcdf-java/v4.3/javadoc/ucar/nc2/FileWriter2.html
> > )
> >
> > and, if you have the C library of netCDF installed, you can directly write
> > out a
> > netCDF-4 file, thus skipping the conversion using NCO.
> >
> > See the first link for more info on the structure of NcML.
> >
> > Cheers,
> >
> > Sean
> >
> > > R/Sir
> > >
> > >
> > > Is there a way to convert raw data to netcdf using XML.
> > >
> > > I read somewhere:
> > >
> > >
> > http://hdf-forum.184993.n3.nabble.com/h5gen-or-any-h5dump-generated-XML-to-HDF5-td3719793.html
> > >
> > > See post by H. Joe Lee....
> > > It states something like this:
> > > Create NcML file (a variant of XML) and use NetCDF-Java to generate an
> > > NetCDF-3  file [1].
> > > Then convert the NetCDF-3 to NetCDF-4 using NCO  [2].
> > >
> > > The converted NetCDF-4 file is HDF5 file.
> > > You got the HDF5 from XML (NcML).
> > >
> > >
> > >
> > > Ghansham
> > >
> > >
> >
> > Ticket Details
> > ===================
> > Ticket ID: SBB-665470
> > Department: Support netCDF Java
> > Priority: Normal
> > Status: Open
> >
> >
> 
> 

Ticket Details
===================
Ticket ID: SBB-665470
Department: Support netCDF Java
Priority: Normal
Status: Open