ntpviz - Don't plot a line during data absence
hmurray at megapathdsl.net
Sun Oct 23 19:08:40 UTC 2016
jason at azze.org said:
> In the interest of keeping longer technical discussions on the devel list,
> we have this:
> <gemiller> hmm, some people use up to poll 1024, I could preprocess the plot
> file so that any gap longer than 1024 seconds does not get a connecting
> line. Sound good? Or would people prefer to see just dots first?
If the polling interval is X, there may be up to 8X gaps in peerstats.
I think it helps to avoid the long lines across missing data.
Lines vs points is an interesting tangle.
Lines work well when the data is smooth. The same data with points turns
into a fat line if the points are dense. (I consider the single dot type of
point to be useless since I can't see an isolated dot on my screen unless I
know where to look.)
If you have occasional outliers, lines mode draws a line up to that sample
and back down. That makes it easy to spot the outliers. If you have more
than occasional outliers that turns into a lot of clutter on the screen and
points mode is probably better.
If the data is not smooth, and the samples are dense, line mode turns into a
broad swath of up and down lines. Points mode has the same problem - the
swath is made up of points rather than line segments. You can solve the
problem by spreading things out in X, or Y if in points mode.
Things get more interesting if you try to plot several sets of data that
I haven't found a good way to automate the decision process. I've been doing
it by hand. A config file to guide that might be interesting. It could also
specify which graphs to plot and/or what to put on a graph.
These are my opinions. I hate spam.
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