This is an implementation of down-sampling as used by the flot charts plugin. This is not really my work, I just translated the code from Javascript and read the thesis.

Implementation in Javascript

My data often has gaps (in time) and I need to cope with that, I also want to cache the down-sampled data and so I have made use of a single interval method. It is likely that this method, in the current implementation will cause rounding errors, this is evident in the example data provided with this package. To cache the data provided by the routine I expect a single interval would be desirable.

I have made use of JFreeChart in my tests, this is just so you can see the actual data and the downsampled data.