Chart with 0/1 values also shows values in-between

Hi guys,

I am using a chart for showing my iPhone presence. The underlying script returns either 0 or 1 and so should the graph display either 0 or 1.

But oddly enough sometimes the graph shows values in-between:

I have never noticed this behavior in OH1.

Is this a problem of the chart? Or the persistence (I am using rrd4j for the charts)? Or is there anything I can do against? Maybe I have to synchronize the refresh rate and the script execution (every minute)?

Any ideas are welcome…


Can you check if this behavior is the same if you change the chart to e.g. one hour?
Maybe its a problem of the resolution?

It’s the problem of RRD. RRD uses only a limited number of values which are calculated to a mean value.
Please read about rrd4j persistence in the openhab wiki
Older values are compressed to meet the goal of a not growing database. Therefore you get mean values for a certain period of time.


Sounds logical. Thanks Andreas!