[Kst] Plotting time values

[Barth Netterfield]

Thanks for the great reply!

Comments below...

On Thu, Sep 27, 2012 at 12:58 PM, Sonic <get.sonic at gmail.com> wrote:

> Thanks. That sounds awesome. I've got Kst2 source code and have started
> reading. Earlier, I had tried with Kst2 to support opening Easyplot files.
> I first tried a plugin and then I thought I'd edit the source itself. But
> for some reasons I dropped the idea.
>

This would not be a data source, but instead would be a substitute for a
".kst" file or for the command line.  I think it is quite do-able.  All of
the concepts in the .ep file that I saw are already in the .kst file
(embedded data, plot and curve description, etc.).

Hmmm...


>
>  The steps involved would be:
>> - looking at the history of the request Barth mentioned on bugs.kde.org(once it's up again, seems to be down right now...)
>> - discussing the details with us here on the list to make sure we're
>> going in the right direction and have a common understanding
>> - adding the options in the GUI + loading/saving them to the .kst file
>> - implementing the parsing of ASCII times and conversion to "double"
>> time, which should be easy with QDateTime methods
>> - testing, first locally on your PC and then you can provide patches
>> which we'll review and integrate :-)
>>
>
> I glanced over the bug report. I'll certainly work on it. But I'm a bit
> busy right now.
>
>
>
:-)

[....]

2. Easyplot is extremely simple to use. I mean I can open an ASCII file
> with nothing but two columns of numbers (x and y) in EP and it directly
> shows a plot. Kst on the other hand first shows me an import dialog where I
> need to select lot of things before I get to see the plot.
>

For 'superfast' reading of ascii files, I do it from the command prompt:

promp% kst2 -x 1 -y 2 data.dat

Reading ascii files like this from the UI is not something that I often do.
 Our data sources have hundreds of fields - hence the nature of the UI.

But: we could add a radio box (with a sticky default) to the first page of
the data wizard:
[ ] Plot all fields vs INDEX
[ ] Plot all fields vs first field
[ ] Select fields and formatting with UI

Thoughts?

3. EP supports putting data and plot information in the same file. (please
> see attached file). The plot header is simple text and we auto generate it
> from our applications. This is a huge advantage over Kst (I'd say a deal
> breaker in adopting Kst) as we generate hundreds (or even thousands in some
> cases) of such plot files from our C++ applications. The files can simply
> be double-clicked and EP would display the plot. No fuss.
> EP supports both ASCII data and binary data (the plot header is ASCII
> either way). Some of us use the latter to reduce the file size while many
> use the ASCII multi-column structure because of its simplicity.
>

kst2 supports the same things in the kst file, including embedded data.
 However, the format is a fairly verbose XML file, which is not trivially
machine readable.  However, a .ep file reader, or a kst to ep converter
could be written.  I would not plan to support saving as an ep file,
however.


> 4. EP supports date and time values. The date needs to be in column-1 and
> time in the next column. The time can even have milli-seconds. This is
> important for us for plotting higher sample rate data.
> We often run data logging that cross midnight boundaries. Without proper
> date support, it is a pain to manually split the files.
>

High on our priority list, as we mentioned.  I will start on it soon if you
can not.


>
> 5. Auto-generation of independent plot files (from C++ applications) is of
> extreme importance to our way of work. I'm not sure if Kst supports this
> (in a convenient form, that is). It must also be possible to edit such a
> plot from the GUI and save to it.
>

This way of working sounds very interesting!

We have python scripting in beta right now, which can do a lot of what one
might want (everything you mentioned at least).  So one might implement the
.ep reader as a python script (?)

6. Another killer feature of EP is that I can right-click and copy a curve
> from one application window and paste it in another for 'over-plotting' two
> data sets. The pasted curve can be moved horizontally or vertically so that
> features from two data sets can be aligned for visual comparison.
>

Sounds very interesting.  Tell me more...



> regards,
>
> Syam
>

thanks for the comments!

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-- 
C. Barth Netterfield
University of Toronto
416-845-0946
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