[ncl-talk] problem with HDF file

David Brown dbrown at ucar.edu
Wed May 3 12:52:55 MDT 2017


Hi Geeta,

As Mary says, NCL does not currently support the Vdata type in HDF4,
but there is a tool called h4toh5 that you can download from the HDF
group site at https://ftp.hdfgroup.org/h4toh5/download.html. It was a
little hard to build on my Mac, but eventually I managed. (I would be
happy to fill you in on the details -- although you may be able to use
the binaries if you are working on Linux.)  It will convert HDF4 files
to HDF5. The Vdata type is converted to the HDF5 compound data type,
which NCL is able to interpret.I
I am attaching a print out of the output from ncl_filedump on the
converted test.h5 file. I will also upload test.h5 to the ftp site so
you can try it for yourself.
You should definitely use NCL 6.4.0 to work with this file. Also you
should read the "File I/O Improvements" section of the latest NCL
release notes (http://www.ncl.ucar.edu/current_release.shtml#FileIOImprovements6.4.0)
for information on working with groups and compound data in NCL 6.4.0.
Hope this helps.
 -dave

On Wed, May 3, 2017 at 12:01 PM, Mary Haley <haley at ucar.edu> wrote:
> Geeta,
>
> This appears to be HDF4 VDATA data, which NCL doesn't currently support. We
> haven't received many requests for this, so it has been very low on our list
> of things to add support for.
>
> I added your email to the ticket we have on this (NCL-1195) in case this
> becomes something we need to support.
>
> Meanwhile, have you checked around to see if this data is available in
> NetCDF format instead?
>
> --Mary
>
>
>
>
> On Tue, May 2, 2017 at 5:59 PM, Geeta Geeta <geetag54 at yahoo.com> wrote:
>>
>> dear ncl users.
>> I have lighening data (orbital) which I wish to plot. the image downloaded
>> from web is attached.
>> but when I doenload the datafile, from the following link.
>>
>> https://lightning.nsstc.nasa.gov/lisib/lis1orbit.exe?which=qc&year=2011&day=104&orbit=76394
>>
>> aditya at agniilap:~/geeta/ncl/MYLIS$ ../bin/ncl trmm.lis.ncl
>>  Copyright (C) 1995-2014 - All Rights Reserved
>>  University Corporation for Atmospheric Research
>>  NCAR Command Language Version 6.2.1
>>  The use of this software is governed by a License Agreement.
>>  See http://www.ncl.ucar.edu/ for more details.
>>
>> Variable: hdf4_file
>> Type: file
>> File path: ./test.HDF
>> Number of global attributes: 0
>> Number of dimensions: 0
>> Number of variables: 0
>> warning:getfilevarnames: test contains no variables readable by NCL
>> (0) missing
>> I get this message.
>>
>> pls help me how to check the data file.
>>
>> Geeta.
>>
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>
>
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