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Hi, I noticed in your blog that the chart uses data-sampling, so if I create a WPF line chart with 10,000 points, I am assuming that only a subset are rendered. Do I have any control over sampling? i.e. is there any way I can tell when it is being used? or can I disable it? Thanks. |
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Hi, I came here to ask the same. Is it possible to change the resampling at all? Jose |
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Hello and sorry for the late reply. At the moment there are no hooks for controling the data sampling and there is no option to disable it. But we can add these in. Data sampling simply skips over a consistent number of data points when iterating through the data. So every 2nd point or every 3rd point etc gets displayed based on the total number of points that fit within the viewport. Note that the most minimum and most maximum point will always be displayed. To what level do you want to be able to control the data sampling? Could you please describe any usage scenarios to help us determine what hooks to implement. - Jason |
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Hi, I find resampling in a chart a deal breaker because it can potentially mislead the viewer. One example is using data visualization to spot outliers. If the data sampling is blindly dropping data points then some of the outliers will not be drawn and will be missed. Ideally it would be possible to define the resampling function, but in a first phase I would create a property that sets the value when the chart starts reampling. I would contend that batching is a better solution that resampling. It is not a replacement but good batching support will be a more useful and practical way to show large numbers of datapoints in a chart. Jose |
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Hello We have now provided a DataSeries.IsDataSamplingUsed property which will be set to true whenever the data series is using data sampling which is resulting in some data points being skipped. We have also included a DataSeries.AllowsDataSampling property which you can set to false to disable this feature entirely. Note that scatter series and bar series do not currently support data sampling at all. These properties will be available through the nightly builds from tomorrow the 19th of October from the downloads page: http://www.mindscapehq.com/products/wpfelements/nightly-builds This is very minor support for controling data sampling, but it should give you a place to start. |
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