[rrd-users] Graphing average temperatures

Dan Cech dcech at phpwerx.net
Wed Nov 21 21:42:37 CET 2007

Petteri Matilainen wrote:
> On 11/21/07, Simon Hobson <linux at thehobsons.co.uk> wrote:
>> Petteri Matilainen wrote:
>>> I'm currently graphing daily, weekly, monthly and yearly inside and
>>> outside temperatures. The temperature values are fetched from SQL
>>> database and then put into temperatures.rrd. I have a cron job that
>>> runs this every 5 minutes. Then I wanted to graph average
>>> temperatures too. I didn't think of any other way but to read
>>> average temps from temperatures.rrd and them into a new rrd,
>>> averages.rrd. Then I graph averages.rrd as usual.
>> Why don't you just graph the averages you already have in temperatures.rrd?
> How? I have

On re-reading your post I think you may be confused.

> DEF:Inside=/var/digitemp/temperature.rrd:in:AVERAGE
> LINE1:Inside#3333CC:"Inside"

This line will plot the average temperature for the time period
represented by each pixel on your graph.

> GPRINT:Inside:AVERAGE:"\t%6.2lf °C" <- this is the average I want to
> plot which give me the "ordinary" graph. If I have

This figure is a single number representing the average temperature for
the period of the graph.

> VDEF:avg=Inside,AVERAGE
> LINE1:avg#3333CC:"Average"
> I get a straight horizontal line.

This is correct.  If you plot the average temperature for the graph
period, you will get a line straight across, because it is the same for
the entire graph period.

You will probably get more useful feedback if you post some more details
about the structure of your temperatures.rrd, the data you are
inserting, and what you are trying to achieve.


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