Huge Time series

xihong · Post by **xihong** » Mon Aug 07, 2006 7:49 pm

I have a huge time series (10 years hourly) to display. The total number of data points is about 100,000. Can JFreeChart plot this time series? Is there a limit on the number of data points in JFreeChart?

Thanks

SeanMcCrohan · Post by **SeanMcCrohan** » Mon Aug 07, 2006 8:44 pm

I have one chart that's currently showing 20 series, each with 3 days of per-minute data. That's 86400 data points, and it works fine. 100000 shouldn't be a problem.

I've found the main limiting factor to be heap space, and that has less to do with JFreeChart than it does with parsing the results from the data source to insert them into the JFC datasets.

kelly · Post by **kelly** » Mon Aug 07, 2006 9:13 pm

With the default heap space, I've found that I start to run out with about 800,000-900,000 data points. However, I'm plotting it in about 10 series of 60,000 points each

Mercer · Post by **Mercer** » Mon Aug 14, 2006 3:04 pm

A couple of tricks to reduce memory and such things.

1) Add your points without notification (theres a true/false flag on one of the adds) then add the last one WITH notification. That notification on the last point will go through all the previous points and fix things like range/domain etc.

2) Eliminate the Element collection. (right name?) This creates a little box in memory that corresponds to where your mouse is hovering over the chart so that a handy tool-tip will pop-up telling you which point you're over. Even if you're not using tooltips, this list is created anyway. Lotsa memory for this when you get up there in size.

No there's no limit with JFreeChart with how many points. My current record is 5.2 million.