Sampling data and optimization

[Matei Negriu]

Hi,

My name is Matei Negriu and I work for Ixia (http://www.ixiacom.com)

I have several very large data series (1 000 000 points) and I want to display them at once on the same graph. But ... the graph is getting really crowded, and it also takes a lot of time loading.

Is there any automated way of extracting only some sample data from the original series and showing the graph for optimum performance? Also when zooming I'd like to improve the "resolution": For instance, if I have 1 000 000 points and sample only 200 points for the graph, when I select some area of the graph that I want to zoom, I'd like the zoomed portion to show 200 points as well, so the user might get a more detailed picture.

Are there any performance optimization mechanisms for large data sets available in Chart FX?

Thanks,

Matei Negriu

[JuanC]

ChartFX for WPF will "process" all your data but it will use the size of the chart in pixels to try to draw as few points as possible while retaining visual fidelity with the hole data set.

As far as I can tell what we do is equivalent to sampling the data in the sense that you cannot pick 200 arbitrary points from a 1 000 000 data set as you might be ignoring important spikes in the data. One thing we do that might be affecting the performance you experience is that we keep a copy of the data which in your case might be increasing your load time but should have no effect in the performance repainting the chart.

By delaying the data compression untill draw time we automatically gain resolution as you zoom in the chart.

Unfortunately we do not have any other perf optimization mechanisms in the product at the moment. Can you elaborate on where do you have this data (SQL, Business Objects, etc.) and what load-time/draw-time performance you get? You can drop an email to support at softwarefx dot com if you want to provide more details offline.

JuanC