[rrd-users] Graphing average temperatures

[Dan Cech]

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
>
> DEF:Inside=/var/digitemp/temperature.rrd:in:AVERAGE
> LINE1:Inside#3333CC:"Inside"
> GPRINT:Inside:AVERAGE:"\t%6.2lf °C" <- this is the average I want to plot
>
> which give me the "ordinary" graph. If I have
>
> VDEF:avg=Inside,AVERAGE
> LINE1:avg#3333CC:"Average"
>
> I get a straight horizontal line.

Are you looking for a 'sliding window' average?  If so you might want to
check out the TREND function here:

http://oss.oetiker.ch/rrdtool/doc/rrdgraph_rpn.en.html

Dan