[Kst] Plotting time values

[Sonic]

On 09/24/2012 02:20 AM, Nicolas Brisset wrote:
> Hi Syam,
>
> that's freaking good news! Adding support to read ASCII time as described on bugs.kde.org is not a trivial task (because the ASCII data source has become quite complex) but certainly doable with some Qt/C++ knowledge, and it's a very highly desired feature. You'd gain hero status right away :-) And since we're very interested in the feature, of course we'll support you as best we can.

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.

> 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.


>
> By the way, I can't open the plot you've attached (which easyplot is it, by the way? There seems to be many programs with that name. I guess you mean http://www.amion.com/ep/epfeatures.html, which looks quite similar to Kst, but I'm not sure and I haven't tried it). Do you have a png, jpg or pdf version?

The one we use is an old version, from 'Spiral software'. 
http://www.spiralsoftware.com/
I guess now its called Amion. It's actually very simply, yet very 
powerful and fast. Only problems are the occasional crashes when zooming 
in plots, frequently with time axis plots.

>
> Let us know if you want to give it a chance, it would be perfect timing since Barth is currently working on improving time-based support in the range dialogs.
>
> Nicolas


>
> P.S.: if you're using easyplot, it would be interesting to have your feeling how kst compares to it on real-case scenarios. Performance, usability, etc...

OK. Here goes. Let me first clarify that I work in the space industry - 
testing, in particular.

1. Kst is equally fast, or even faster. But I've never made an objective 
measurement.

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.

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.

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.

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.

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.

7. Apart from occasional FFT, we never use other data 
analysis/manipulation features of EP. At times we scale or shift the 
values using some bulit-in equations support. Otherwise, plotting is 
what we require from the tool and not sophisticated data analysis. I 
have not tried Kst's strengths in this area either.

8. The 'data modes' and zoom modes of Kst are superior to that of EP.

9. Despite the above points, EP has a very primitive UI. But 
surprisingly it works well for no-frills plotting. Kst is way more 
advanced in its plot layouts and things.


regards,

Syam



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