[rrd-users] --alt-autoscale question

[Christian]

Dear list,

thanks for this great piece of software. I am using rrdtool in
pnp4nagios to plot performance data. I am plotting a temperature and
would like the y range to be set by the actual range of the data. So I
modified the corresponding pnp4nagios template to use --alt-autoscale.
Here is the command line pnp4nagios will send:

/usr/bin/rrdtool grap - --width=500 --height=100 --start 139979062
--vertical-label "" --title "lab_e102 / Check lab temperature"
--alt-autoscale

However, the lower limit on the y-axis will never be adjusted and always
remain zero in the plot.

/usr/bin/rrdtool grap - --width=500 --height=100 --start 139979062
--vertical-label "" --title "lab_e102 / Check lab temperature" -l 21.0 -r

will give me a scale that starts at 21.0 Celsius as expected. What am I
missing here? I am attaching a picture of the graph generated with
--alt-autoscale, but I am not sure it will make it to the list. The plot
has values for min and max included, and they are correct, so
--alt-autoscale should work. Thanks,

Christian

PS: This is rrdtool 1.4.7-2 as shipped by Debian wheezy.
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