Trendlines

31 Jul 201714 minutes to read

EjChart can generate Trendlines for Cartesian type series (Line, Column, Scatter, Area, Candle, HiLo etc.) except bar type series. You can add more than one trendline object to the trendlines option.

JAVASCRIPT

/// <reference path="tsfiles/jquery.d.ts" />
/// <reference path="tsfiles/ej.web.all.d.ts" />

module ChartComponent {
    $(function () {
        var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Enable Trendline to chart series
                       visibility: "visible", type: "linear"
                     }],
                //...
              }]          
             //...  
        });
    });
}

Customize the trendline styles

A trendline can be customized by using the properties such as fill, width, dashArray and opacity. The default type of trendline is “linear”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                         //...
                         //Customize the Trendline styles
                         fill: '#99CCFF', width: 3, opacity: 1, dashArray: '2,3'
                     }],
                //...
              }]          
             //...  
        });

Types of Trendline

EjChart supports the following type of Trendlines.

• Linear
• Exponential
• Logarithmic
• Power
• Polynomial
• MovingAverage

Linear

To render Linear Trendline, you have to set the type as “linear”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type
                       type: "linear"
                     }],
                //...
              }]          
             //...  
        });

Exponential

Exponential Trendline can be rendered by setting the type as “exponential”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type
                       type: "exponential"
                     }],
                //...
              }]          
             //...  
        });

Logarithmic

Logarithmic Trendline can be rendered by setting the type as “Logarithmic”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type
                       type: "logarithmic"
                     }],
                //...
              }]          
             //...  
        });

Power

Power Trendline can be rendered by setting the type of the trendline as “power”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type
                       type: "power"
                     }],
                //...
              }]          
             //...  
        });

Polynomial

Polynomial Trendline can be rendered by setting the trendline type as “polynomial”. You can change the polynomial order by using the polynomialOrder of the trendlines. It ranges from 2 to 6.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type
                       type: "polynomial"
                     }],
                //...
              }]          
             //...  
        });

MovingAverage

MovingAverage Trendline can be rendered by setting the type of the trendline as “movingAverage”.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //Change Trendline type and set [`period`](../api/ejchart#members:series-trendlines-period) for moving average
                       type: "movingAverage", period: 3
                     }],
                //...
              }]          
             //...  
        });

Forecasting

Trendline forecasting is the prediction of future/past situations. Forecasting can be classified into two types as follows.

• Forward Forecasting
• Backward Forecasting

Forward Forecasting

The value set for forwardForecast is used to determine the distance moving towards the future trend.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //...
                       //Set forward forecasting value
                       forwardForecast: 5
                     }],
                //...
              }]          
             //...  
        });

Backward Forecasting

The value set for the backwardForecast is used to determine the past trends.

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //...
                       //Set forward forecasting value
                       backwardForecast: 5
                     }],
                //...
              }]          
             //...  
        });

Trendlines Legend

To display the legend item for trendline, use the name property. You can interact with the trendline legends similar to the series legends (show/hide trendlines on legend click).

JAVASCRIPT

var chartsample = new ej.datavisualization.Chart($("#chartcontainer"), {
            series:[{
                  trendlines: [{
                       //...
                       //Set Trendline name to display in the legend
                       name: 'Linear'
                     }],
                //...
              }]          
             //...  
        });