Use regression line for projection about highcharts_trendline

[vigneshwaranr]

I second this

[cstefano]

The calculation of the trend line (regression) data points is independent to HighCharts, so you can extrapolate the projected value mathematically, using the slope and y-intercept that is calculated by the fitData function.

For linear regressions the formula is y = mx + c. Where m = slope and c = y-intercept, so given an x value, you can calculate the y value.

[virtualstaticvoid]

I've built in support for calculating projected x or y values to the regression. See demo5.html for an example.

E.g.

// define data array
var sourceData = [
  [106.4, 271.8],
  [295.6, 432.3],
  [129.9, 133.2],
  [144.0, 134.7],
  [216.4, 319.2],
  [435.6, 665.3]
];

var linRegression = fitData(sourceData);

// project starting and ending values
var projectedX = linRegression.x(50);
var projectedY = linRegression.x(500);

// insert projected values into the array
var linRegressionData = linRegression.data;
linRegressionData.unshift([projectedX, 50]);
linRegressionData.push([500, projectedY]);

// use linRegressionData for the data for the trend line on the chart 
...