[Kst] plotting lots of high resolution data

[Andrew Walker]

Hi Iain,

Kst reads in values as double values, so they should be good to 14 
significant figures.

Using only the data you provided in the email I am able to display a time on 
the x-axis by doing the following:

Create the plot, with column 1 as the x-vector and column 2 as the y-vector 
(presumably what you have already done)
Right click on the plot and select Edit...
Click on the "X Axis" tab
Check the checkbox to the left of "Interpret as:" and select "Standard C 
time" in the combobox to the right.
Select the desired item in the combobox to the right of "Display as:"

I believe this should give you what you are looking for. A screenshot is 
attached.

Difficulties may arise if your time format is not a supported one.
In that case you need to first use an equation to convert the time format to 
a time in one of the supported formats.

Andrew

----- Original Message ----- 
From: "Iain Buchanan" <iaindb at netspace.net.au>
To: <kst at kde.org>
Sent: Saturday, August 21, 2010 12:38 AM
Subject: [Kst] plotting lots of high resolution data


> Hi all,
>
> I've been playing around with a couple of graphing tools to improve on a
> SCADA trending tool I use regularly, but there are some things I haven't
> been about to figure out in a couple of hours!
>
> First, how fine can kst handle time values?  We plot various types of
> data from years of slow temperature values (ie once per second) to
> months of fast power / frequency at 100ms or so, to high speed
> disturbance data imported from power meters (such as 10 seconds worth of
> 20ns sampled points).  Except for the last example, the rest of the data
> is "differentially" recorded not sampled, ie. depending on the rate of
> change of the data, the distance between any two data points will be
> different.
>
> I've imported an example of about 170,000 samples which look a bit like
> this (the data is actually in a binary format but I've converted it to
> csv for now):
> 1273262911.3214,-19.034
> 1273262919.6692,-16.315
> 1273262950.9138,-1.607
> 1273262950.9718,-5.562
> 1273262951.0178,2.719
> 1273262951.1118,5.809
> 1273262951.3128,2.101
> 1273262951.4188,-0.618
> 1273262951.4668,-3.708
> 1273262951.5138,-8.899
> 1273262951.5737,-13.225
>
> As a pure x,y scatter plot, kst handles this perfectly!  However the x
> axis shows labels such as "+[1.0e+05]".  When I try and interpret the
> data as a time, nothing changes on the x-axis.  Probably because it's
> down to hundreds of micro-seconds rather than just ms, and I assume this
> is too fine for the a kst time?
>
> What format should a ms time be in?  I found a post here about ms time:
> http://mail.kde.org/pipermail/kst/2008-December/016025.html but I didn't
> see any response further than "yes it's possible".
>
> I could get around this and deal with data down to ns or further if
> there was a way of putting my own labels on the x-axis.  For example, at
> "1273262951.5737" I could put a text label of "8/5/2010" or "05:39:11"
> depending on the zoom level.
>
> I'm happy to hear your thoughts / suggestions!  thanks,
> -- 
> Iain Buchanan <iaindb at netspace dot net dot au>
>
> Historically Tcl has always stored all intermediate results as strings.
> (With 8.0 they're rethinking that.  Of course, Perl rethought that from
> the start.)
>             -- Larry Wall in <199710071721.KAA19014 at wall.org>
>
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> https://mail.kde.org/mailman/listinfo/kst
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