[rrd-users] More comfortable chart display
rrdtool at martin.sperl.org
Sun Jan 25 15:17:55 CET 2009
A colleague of mine has written a java-script a few years ago that was
able to take a dynamically created rrd-graph (based on a cgi-script that
takes arguments for start, end, min and max) and allowed us to zoom into
the image by selecting the "interresting area". Sadly this code is no
longer available to me (and also a copyright issue...).
This was working quite well, but was not perfect, as we were not able to
enlarge the size of the image itself, as then all the scaling would have
gone astray. Other effecting parameter are: Label of Y-Axis, Title
(maybe multiline), font-size,... So there is the need to get the scale
and the "graph area within the image" without to much guesswork or
assumptions about the graph layout.
So what I see that you would need to create is:
* a cgi-script tat can create the graph dynamically based on the
arguments you give - I believe that several people have creates some
cgis like these, but as usual these tend to be highly "use-case"
specific... This is really not very complex and you should be able this
with a few lines of perl/php/ruby code (depending on available language
the image as soon as the selection is done.
Then you should be able to handle your requirements for showing such a
graph without having to create a separate graphing tool, which would
introduce additional overhad and lead you to reinventing the wheel like
how to do "Axis labels" placements (which RRD tool is handling quite nicely)
To avoid the "scaling" problems within the Image itself, maybe we
should think of how we can extend rrdtool so that it can embed the
drawing area and the X/Y-scale information into the PNGs or JPGs - e.g.
information for scale calculations.
(For the JavaScritpt accessing the information this code maybe a
Actually I believe that a few people would like such a capability for
> I don't want to complain about the way RRDTOOL displays recorded data. I'm
> explicitly quite
> happy with all the options RRDTOOL offers!
> Nevertheless, I'm looking for an other tool which can display the stored
> data (I converted them to XML)
> in a more comfortable way.
> The reason is , I'm logging about 30 temperatures over a period of 3 month
> any minute. The data base
> is organized that way, that I can get all one minute temperatures over the
> hole 3 month. My problem
> now is to select a certain time area of my interest and zoom it, so I can
> identify the results of
> certain external events. That is a bit difficult to realize with RRDTOOL
> GRAPH and quite time-consuming.
> (provided I used the right features of that really powerful tool).
> Does anybody know a tool which allows to display a XML data set generated by
> rrdtool , in a way I could
> quickly move to a certain time position and quickly zoom in the area around
> that position ? I would
> prefer a tool running on Windows, but Linux would also be ok.
> Thank you very much.
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