[ncl-talk] problem with HDF file

Sun May 7 08:51:50 MDT 2017

Geeta,

I'm still not sure what you want. You said that the lat/lon of the two
datasets don't match. Do you need them to "match" so you can do
calculations using data from both files? If so, then you will likely need
to regrid the point data to be on the same grid as the swath data, which
you can do with ESMF regridding:

http://www.ncl.ucar.edu/Applications/ESMF.shtml

See example ESMF_regrid_21.ncl as a start, which regrids from point data to
rectilinear data. Your swath data is likely curvilinear and not
rectilinear, but the example will be similar.

You can also visit the "templates" page:

http://www.ncl.ucar.edu/Applications/Templates/

and look at the "ESM_unstruct_to_curv.ncl" template script.

--Mary

On Fri, May 5, 2017 at 9:00 AM, Geeta Geeta <geetag54 at yahoo.com> wrote:

> Hi Mary and dave.
> Thank you for plotting the Lightning data for me.
>
> I am using two datasets, LIS (Lightning, which is in HDF4 had issue with
> this file), and 2A25 which has reflectivity at 80 levels, both are Orbital
> data sets but with different swaths. Pls see the figures.
>
> Lis is plotted at the locations where Lightning is seen. I have to extract
> the maxZ  at the locations where Lightning is seen (pls see the code, this
> would be 4th level of filtering that I will be doing to my Reflectivity
> data, ref to fig4.000007.png).
>
> My purpose is to show that "*severe storms *are the ones that have
> lightning associated with them". Rest can be called as convective echoes.
>
> My problem is that the Lat/lon of both datasets Do not match. One is a
> point data and the other is a swath data.
>
> I want to know if it is possible to do??? and how, what logic
>
> you all do a great job in helping us. That is why i am able to move ahead
>  thanks
> Geeta.
>
>
> On Friday, 5 May 2017 4:05 AM, Mary Haley <haley at ucar.edu> wrote:
>
>
> Geeta,
>
> I'm not clear on your question about extracting 2A25 reflectivity data
> depending on non-zero data of LIS. The text file I was looking at yesterday
> had no header information, so I have no idea what the various columns mean.
>
> Also, you attached two plots, but I'm not sure if you are trying to ask a
> specific question about them.
>
> I just plotted every lat/lon point that you had, which is what I assume is
> what you used to create the lightning marker plot. Is there something more
> you need to do with this particular plot?
>
> As for the contour plot with the labelbar, I'm assuming this is the
> reflectivity plot, but again, what is the "non-zero data of LIS"? Is LIS
> one of the columns of data in your ASCII file?
>
> You need to be more specific about what you need.
>
> --Mary
>
>
> On Wed, May 3, 2017 at 11:06 PM, Geeta Geeta <geetag54 at yahoo.com> wrote:
>
> Thanks Mary and Dave.
> these files are not avaible in netcdf.  Mary's script is plotting it when
> input file is txt.
> I have to try that HDF4->HDF5 tool.
>
> Pls tell me when u upload the script for it's conversion to H5.
>
> I actually have to extract 2A25 reflectivity data depending on non-zero
> data of LIS. I am attaching the Figures.
>
> I dont know how to do using the txt file.
>
> thanks
>
> Geeta.
>
>
> On Thursday, 4 May 2017 12:22 AM, David Brown <dbrown at ucar.edu> wrote:
>
>
> 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.
> <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
> <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
> <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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