Anomalies in Gnuplot (fwd)

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Anomalies in Gnuplot (fwd)

Dave Horsfall
Am I the only one with these (allegedly minor) problems?

--
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."

---------- Forwarded message ----------
Date: Wed, 1 Jun 2016 10:08:29 +1000 (EST)
From: Dave Horsfall <[hidden email]>
To: Gnuplot Mailing List <[hidden email]>
Subject: Anomalies in Gnuplot

Gnuplot 5.0 pl 3, on MacOS 10.11.5

I'm seeing a couple of glitches in Gnuplot, and I cannot see where I
stuffed up.

Browse over to www.horsfall.org/gptest and view the files therein; they
are a cut-down version of a script I use to plot my BP etc (note that my
dates use the format d/m/y, as I am not American; later graphs use the
more conventional yy/mm/dd, which actually sorts).

The gap towards the end of April is where I spent a week in hospital, but
note the sole dot in the middle; there is no datum for it, and anyway I
don't recall dashing home midway through my unintended confinement :-)

What would be causing it?  It's driving me nuts.

The other glitch is the datum for 18/4/16 (146), which did not go off the
scale but should have (at the time my scale was 0:140, since a BP of over
140 means Trouble), but that's not so important.

Help, anyone?

--
Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."

------------------------------------------------------------------------------
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patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
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Re: Anomalies in Gnuplot (fwd)

zowie
It looks correctly plotted to me.  

Looking at your .dat file: you’re missing a point on 17-April-2016, then you’ve got two points
18-April-2016 and 19-April-2016, both with systolic of 146 (correctly plotted on the Y axis
which goes to 160). Those are correctly rendered as a short horizontal line segment between
the two data.

After that you’ve got a stay in hospital.

So it looks like your “glitch” isn’t you running home from hospital, it’s you being sick for a day
and breaking the progression.

The gap before 18-April may appear larger because the missing point on 17-April loses you
*two* line segments: 16-17 and 17-18.  

You might like to plot this chart with histeps or linespoints rather than with lines:  line
plots like this are not as useful for understanding point-by-point progressions of missing or
error-prone data.  For that type of analysis, “histeps” is a better choice: you still get the
eye-pleasing connectivity of “lines”, but a more rigorous and less counterintuitive treatment
of sampled and missing intervals.

Note that the above does not describe a problem with gnuplot, but rather with the practice of
drawing plots of noisy (and potentially missing) data by connecting sampled points with straight
lines.

> On Jul 13, 2016, at 5:15 PM, Dave Horsfall <[hidden email]> wrote:
>
> Am I the only one with these (allegedly minor) problems?
>
> --
> Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."
>
> ---------- Forwarded message ----------
> Date: Wed, 1 Jun 2016 10:08:29 +1000 (EST)
> From: Dave Horsfall <[hidden email]>
> To: Gnuplot Mailing List <[hidden email]>
> Subject: Anomalies in Gnuplot
>
> Gnuplot 5.0 pl 3, on MacOS 10.11.5
>
> I'm seeing a couple of glitches in Gnuplot, and I cannot see where I
> stuffed up.
>
> Browse over to www.horsfall.org/gptest and view the files therein; they
> are a cut-down version of a script I use to plot my BP etc (note that my
> dates use the format d/m/y, as I am not American; later graphs use the
> more conventional yy/mm/dd, which actually sorts).
>
> The gap towards the end of April is where I spent a week in hospital, but
> note the sole dot in the middle; there is no datum for it, and anyway I
> don't recall dashing home midway through my unintended confinement :-)
>
> What would be causing it?  It's driving me nuts.
>
> The other glitch is the datum for 18/4/16 (146), which did not go off the
> scale but should have (at the time my scale was 0:140, since a BP of over
> 140 means Trouble), but that's not so important.
>
> Help, anyone?
>
> --
> Dave Horsfall DTM (VK2KFU)  "Those who don't understand security will suffer."
>
> ------------------------------------------------------------------------------
> What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
> patterns at an interface-level. Reveals which users, apps, and protocols are
> consuming the most bandwidth. Provides multi-vendor support for NetFlow,
> J-Flow, sFlow and other flows. Make informed decisions using capacity planning
> reports.http://sdm.link/zohodev2dev
> _______________________________________________
> gnuplot-info mailing list
> [hidden email]
> Membership management via: https://lists.sourceforge.net/lists/listinfo/gnuplot-info
>


------------------------------------------------------------------------------
What NetFlow Analyzer can do for you? Monitors network bandwidth and traffic
patterns at an interface-level. Reveals which users, apps, and protocols are
consuming the most bandwidth. Provides multi-vendor support for NetFlow,
J-Flow, sFlow and other flows. Make informed decisions using capacity planning
reports.http://sdm.link/zohodev2dev
_______________________________________________
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