[Kst] stripchart question
walstra at science.uva.nl
Fri Nov 4 16:45:35 CET 2005
On Friday 04 November 2005 15:53, Barth Netterfield wrote:
sorry this is not what I meant. We've been using that for a few experiments
for slow datastreams to monitor 50+ sensors. However I want to plot for
example 10 streams with different frequencies (some are at 1 Hz, others at
50Hz for example) and sometimes lots of data. For this we use a hacked c++
program which needs some refreshing, so I was wondering if a small interface
to kst would be a nice solution. Writing the data from 3 different tcp
sockets (each containing n streams) first to file and let kst update this is
not a real solution. I only want to send the data directly to the plot from a
small program and use kst as backend.
> Stripcharts were the first use of kst.
> In the 'Data Range' widget, (the data range widget is in any dialog where
> you are specifying a range of points to read) select 'Count from end' and
> then put, eg, 1000 in the 'Range' entry. Then the last 1000 points of the
> file will be plotted. If new data is added to the end of the file, the
> plot will be updated and the plot will move to the left as requested.
> Similarly, you can just hit the 'Read from end' icon on the tool bar to put
> all plots into 'count from mode'.
> Similarly, imagine 'data.dat' is an ascii file with data being appended to
> the end. From the command line, you can, eg:
> kst -y 1 -y 2 -m 1 -n 1000 data.dat
> to plot the last 1000 points in stripchart mode of col 1 and col 2 of
> In the menu under 'Setting->Configure Kst' you can change 'Plot update
> timer:' to set how often kst polls the file to see if new data has arrived.
> 300ms is a good value here.
> Does this help?
> On November 4, 2005 12:30 am, Taco Walstra wrote:
> > Hi,
> > I need a stripchart for plotting data from a realtime application.
> > Perhaps you can point me if kst can be easily configured in some way to
> > handle this. I need several plots in kst, the number is however variable
> > and changes during operation. I have looked at the dcop interface, but
> > unfortunately almost no information is available for several functions.
> > It's possible to start plots from a Qt application of course, but it
> > needs a lot of programming for shifting the complete datavector to the
> > left to have a stripchart I presume. Has anybody done such thing? Is the
> > java scripting a better way of handling this and if yes how?
> > Taco Walstra
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> > Kst at kde.org
> > https://mail.kde.org/mailman/listinfo/kst
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