Clickable large sampling data

[Leonardo]

Hello,

i'm trying to use Telerik Silverlight Chart to present a 30.000 points clickable graph. 
I choose to use a 1000 points sampling graph and I configure my event "DefaultView.ChartArea.ItemClick" to be fired each time the user click to one point.

My problem is that my graph isn't precise AND that it isn't showing the true values binded.
I tried to modify my sampling function without succes.

I atach to this thread a image of my rended graph. The red region is where the user points his mouse and always get the tooltip "Date: 15/04/2009 Value: 0".  This point doesn't value 0.

I will add also my graph configuration code:

          Dim lineSeries As New LineSeriesDefinition()
        lineSeries.ShowItemLabels = False
        lineSeries.ShowPointMarks = False
        lineSeries.ShowItemToolTips = True
        lineSeries.Appearance.Stroke = New SolidColorBrush(Colors.Blue)
        lineSeries.Appearance.StrokeThickness = 1

        Dim dataMapping As New SeriesMapping()
        dataMapping.SeriesDefinition = lineSeries
        dataMapping.ItemMappings.Add(New ItemMapping("Value.DateHeure", DataPointMember.XValue))
        dataMapping.ItemMappings.Add(New ItemMapping("Value.Valeur", DataPointMember.YValue))
        dataMapping.ItemMappings(1).SamplingFunction = ChartSamplingFunction.Min

        rcGraphPoint.SeriesMappings.Clear()
        rcGraphPoint.SeriesMappings.Add(dataMapping)

        rcGraphPoint.DefaultView.ChartArea.AxisY.MinValue = 0
        rcGraphPoint.DefaultView.ChartArea.AxisY.AutoRange = True
        rcGraphPoint.DefaultView.ChartArea.AxisX.AutoRange = False
        rcGraphPoint.DefaultView.ChartArea.AxisX.MinValue = lPoints._liste.First.Key.ToOADate
        rcGraphPoint.DefaultView.ChartArea.AxisX.MaxValue = lPoints._liste.Last.Key.ToOADate
        rcGraphPoint.DefaultView.ChartArea.AxisX.Step = 7
        rcGraphPoint.DefaultView.ChartArea.AxisX.LabelStep = 2
        rcGraphPoint.DefaultView.ChartArea.AxisX.DefaultLabelFormat = "dd/MM/yy"
        rcGraphPoint.DefaultView.ChartArea.AxisX.LabelRotationAngle = 60
        rcGraphPoint.DefaultView.ChartArea.AxisX.LayoutMode = AxisLayoutMode.Inside
        rcGraphPoint.DefaultView.ChartArea.LabelFormatBehavior = LabelFormatBehavior.None
        rcGraphPoint.DefaultView.ChartArea.EnableAnimations = True

        AddHandler rcGraphPoint.DefaultView.ChartArea.ItemClick, AddressOf rcGraphPoint_Click
        AddHandler rcGraphPoint.DefaultView.ChartArea.ItemToolTipOpening, AddressOf rcGraphPoint_ItemToolTipOpening

        rcGraphPoint.DefaultView.ChartLegend.Visibility = Windows.Visibility.Collapsed
        rcGraphPoint.SamplingSettings.SamplingThreshold = 1000

        rcGraphPoint.ItemsSource = lPoints._liste

Thanks for your answers!

[Evgeni "Zammy" Petrov]

Hi Leonardo,

What happens when you change the sampling function?

dataMapping.ItemMappings(1).SamplingFunction = ChartSamplingFunction.Average

 

In your example it is set to Min in the ItemMapping and getting a 0 value is the right behevior.

Here you can read about our sampling functionality:
http://www.telerik.com/help/silverlight/radchart-features-sampling.html

Best wishes,
Evgeni "Zammy" Petrov
the Telerik team