[Kst] Support for NetCDF4 files: yes or no?

[Nicolas Brisset]

Hi Joseph,

----- Mail original -----
> De: "Joseph W. Fowler" <joe.fowler at nist.gov>
> À: kst at kde.org
> Envoyé: Jeudi 24 Janvier 2013 02:40:47
> Objet: [Kst] Support for NetCDF4 files: yes or no?
> 
> Dear kst team:
> 
> I'm considering new data file format options for a scientific data
> set, and I am attracted to the "ragged arrays" supported by NetCDF
> version 4.  It goes without saying that I'll want to use kst to
> visualize the data in real time and after the fact.  I see from the
> mailing list (July 2012) that Ross Williamson has privately made
> mods to kst's netCDF plugin that would support version 4 files, but
> I gather that this support isn't in the release version of kst2.
>  (Not sure, though.  Perhaps I am just making NetCDF4 files that are
> invalid in some way.)
I'm not aware of useful patches that we'd have forgotten to apply. If
it is indeed the case, we have to look at that.
As far as I remember, he asked whether someone was working on it. I don't
think it is the case, so any changes he could have made would be interesting
to the wider community. I'm CC'ing him he case he has something he's willing 
to share.
Regarding the support for version 4 files, if you build against a recent 
netCDF library it should be supported. @Peter: which library did you use for 
the Mac build mentioned below?

However note that according to the dimensions used for your variables they 
may not appear in the lists. The data wizard will only show you variables 
which can be handled as vectors (or you've found a bug, send a sample file
so that we can check - or the output of netcdf -h).

> The python script below makes simple NetCDF files in each of 4
> flavors (provided that you have py-netCDF4 installed, of course).
>  My kst2 correctly recognizes the two NetCDF3 files as NetCDF, but
> it recognizes the two NetCDF4 files as ASCII (which is technically
> true, but unhelpful).
> 
> I am using the compiled Mac OSX disk image downloaded yesterday from
> source forge, kst version 2.0.6 (Revision 1307223), on an OS 10.8
> (Mountain Lion) Mac Pro.
> 
> My questions are:
> 
> 1. It seems like standard kst2 doesn't read NetCDF4 files.  Is that
> true?
See above, provided that you use a recent and properly built netcdf library
all versions should be recognized.

> 2. If not, is such a feature imminent, likely, or possible?
Should be easy to do.

> 3. Another thread on this mailing list seemed to state that NetCDF
> files cannot be used in live (streaming) mode.  True?
>From what there is in the source, I'd say growing files (live streaming)
are supported. However I could never test it. I don't have  py-netCDF4
installed, I can't try it right now but if you can do a script that adds 
data to an existing netcdf file I'd be interested to know whether it works.
 
> If the answers are "true", "not imminent", and "true" then I guess I
> should choose dirfiles/getdata instead.
That's certainly also a format to consider.
 
Nicolas