[rrd-users] --alt-autoscale question

[Christian]

All,

thanks for the hints. I have been able to figure it out. There was a
line I had to remove which was responsible for the "shadow" underneath
the line. Thanks,

Christian

Am 12.05.2014 00:04, schrieb Steve Shipway:
>> /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.
> 
> The graph you attach appears to show a Y-axis lower limit of less than zero
> (see the gap at the bottom).  Maybe something like -1.   The autoscale is
> clearly starting around the data value, but something is expanding it down
> to -1 or thereabouts.  Unless you can supply us with the complete RRDTool
> graph command line for comparison it makes it very difficult to identify the
> reason -- possibly you have an additional line on the graph or something
> we're not aware of.
> 
>> /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,
> 
> In this example, you force a lower limit of 21 and use -r (rigid) to lock it
> from expanding, so you get what you asked for (though it is hardcoded and
> not automatically adjusted).  The upper limit will still expand to whatever
> your data maximum is.
> 
> If you omit the -r, do you get a graph like you want, or does it go back to
> zero or less?  If the former, it might indicate a problem in the
> alt-autoscale code, but I would expect you'd get the latter indicating that
> it is the autoexpansion of the Y-range caused by some additional graph lines
> or data that you have not  shown.
> 
> Steve
> 
> Steve Shipway
> s.shipway at auckland.ac.nz
>