How to modify settings in my chart

[Fabios1989]

Hello,
I've got the following chart:



built using TimeSeriesCollection as dataset and XYLineAndShapeRenderer as renderer.
I'd like to modify:
1) for every step, there should be only one value (example, there must not be a serie of "20" or "5", but only one of them);

Can someone help me, please?
Thanks.

[david.gilbert]

It looks like your dataset contains one item every hour of the day. Try adding a new data point only when the value changes.