RadChart Spline ChartSeries not displayed correctly

[Claudio]

Hi,
here you can see my code:

<telerik:RadChart ID="RadChart12" runat="server" Width="600px" Height="400px" DataSourceID="SqlDataSource12" AutoLayout="true" SeriesOrientation="Vertical" Style="float: left;">
            
            <ChartTitle TextBlock-Text="Slot History" TextBlock-Appearance-TextProperties-Color="#333333" Appearance-FillStyle-MainColor="Transparent"></ChartTitle>
             <Appearance Border-Color="Transparent" >
                    <FillStyle   MainColor="Transparent" />               
               </Appearance>
            <Legend Visible="false">
                <Appearance ItemTextAppearance-TextProperties-Color="White" FillStyle-MainColor="Transparent" GroupNameFormat="#VALUE">
                </Appearance>
            </Legend>
            <Series>
            
                <telerik:ChartSeries Name="Total Trains" DataYColumn="count" >
                    <Appearance>
                       
                        <LabelAppearance Visible="FALSE"></LabelAppearance>
                        <FillStyle MainColor="#fbb03b" SecondColor="#fbb03b" >
                        </FillStyle>
                    </Appearance>
                    
                </telerik:ChartSeries>
                <telerik:ChartSeries Name="Cumulative Percentage" YAxisType="Secondary" DataYColumn="Pct_To_Total" DataLabelsColumn="labelPerc" Type="Spline">
                     <Appearance>
                     
                     <TextAppearance  TextProperties-Color="Black"></TextAppearance>
                        
                        <FillStyle  MainColor="Red">
                        </FillStyle>
                    </Appearance>
                </telerik:ChartSeries>
            </Series>
            <PlotArea Appearance-FillStyle-MainColor="Transparent" Appearance-FillStyle-SecondColor="Transparent" >
                        <YAxis2 Appearance-TextAppearance-TextProperties-Color="#333333" Appearance-MajorGridLines-Visible="false" Appearance-MinorGridLines-Visible="false"></YAxis2>
                        <YAxis Appearance-TextAppearance-TextProperties-Color="#333333" Appearance-MajorGridLines-Visible="false" Appearance-MinorGridLines-Visible="false"></YAxis>
                        <XAxis  Appearance-LabelAppearance-RotationAngle="45"  Appearance-TextAppearance-TextProperties-Color="#333333" DataLabelsColumn="slotcount" Appearance-MajorGridLines-Visible="false" Appearance-MinorGridLines-Visible="false">
                        </XAxis>
            </PlotArea>
        </telerik:RadChart>

here the sql result:

slotcount	count	pc_to_total	labelPerc
n°1 Slot	24	6.25	6.25%
n°2 Slot	3	7.81	7.81%
n°10 Slot	1	10.42	10.42%
n°11 Slot	1	13.28	13.28%
n°333 Slot	1	100	100.00%

and here the result:



My problem is that the line does not have to go down and it happens when i use type=Spline to have the curved line...
Can You please help me to understand if this is my fault or if this is telerik issue and can i do anything to show a correct curved line?

[Petar Kirov]

Hi Claudio,

What you identify as a problem is actually caused by the nature of spline algorithms.

The curve between 2 points P1 and P2 actually depends on the points before and after them.

For example in order to draw a smooth curve between n°10 Slot and n°11 Slot, you have to take into account that the next value at n°333 Slot is quite high (compared to the previous two) and should first bend down to leave some room for the turn at n°11 Slot or otherwise the turn will be too sharp.

This may show seemingly wrong trend in situations like this, but this is how smoothness is achieved. If this is a problem, you can always use line series, instead of spline.

Kind Regards,
Petar Kirov
the Telerik team