Groups > comp.graphics.apps.gnuplot > #358

Re: Appending data to existing plot

From	sfeam <sfeam@users.sourceforge.net>
Newsgroups	comp.graphics.apps.gnuplot
Subject	Re: Appending data to existing plot
Followup-To	comp.graphics.apps.gnuplot
Date	2011-06-02 16:47 -0700
Organization	gnuplot development team
Message-ID	<is97e8$s3r$1@dont-email.me> (permalink)
References	<315104e5-99fb-4cc5-8670-5be14fcb4d49@q12g2000prb.googlegroups.com>

Followups directed to: comp.graphics.apps.gnuplot

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Michalk wrote:

> I have used Gnuplot off and on for maybe 15 years now.  It seems that
> by now, it would be possible to add a single datapoint to an existing
> file.  

An existing data file or an existing output (plotted) file?
Gnuplot has no problem with the former - just hit "replot" and it will
use the expanded data file.  Depending on what type of output file has
been created (PostScrip? PNG?), it might or might not be possible to 
add new points.  But in most cases I think it would not be worth the
effort to do it that way, even if possible.

> I checked the patches, and didn't see anything there.  Is there
> any interest in this?

It might be helpful to head more details about your specific use. 

> What I do now, using a Perl interface is to maintain the queue of data
> in Perl and plot a new graph for each new datapoint.  Normally this is
> not a problem, but the target system is an embedded, fanless system
> running at 800MHz, and doing other tasks as well.  The Gnuplot
> overhead is becoming an issue.  If the queues were maintained inside
> of Gnuplot, it could be made more efficient.

Is there a requirement to update the plot for every new point, or only
on demand?  Unless the number of points is huge, I wouldn't expect 
update-on-demand to consume any more resources than appending an incremental
new plot containing only the new point[s].

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Thread

Appending data to existing plot Michalk <michalk@awpi.com> - 2011-06-02 11:22 -0700
  Re: Appending data to existing plot sfeam <sfeam@users.sourceforge.net> - 2011-06-02 16:47 -0700
  Re: Appending data to existing plot Hans-Bernhard Bröker <HBBroeker@t-online.de> - 2011-06-03 20:22 +0200

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