D3.js curveMonotoneX() Method

Last Updated : 09 Sep, 2020

The d3.curveMonotoneX interpolator assumes that the data is sorted according to the x coordinates otherwise sort the data accordingly. This curve method produces a cubic spline that preserves monotonicity in y, assuming monotonicity in x.

Syntax:

d3.curveMonotoneX()

Parameters: This method does not accept any parameters.

Return Value: This method does not return any value.

Example 1:

html

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <script src= "https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.2/d3.min.js">  </script> </head> <body> <h1 style="text-align:center; color:green;"> GeeksforGeeks </h1> <center> <svg id="gfg" width="250" height="250"></svg> </center> <script>  var data = [  {x: 0, y: 0},  {x: 1, y: 3},  {x: 2, y: 15},  {x: 5, y: 1},  {x: 6, y: 15},  {x: 7, y: 5},  {x: 8, y: 19}];  var xScale = d3.scaleLinear()  .domain([0, 8]).range([25, 200]);  var yScale = d3.scaleLinear()  .domain([0, 20]).range([200, 25]);  var line = d3.line()  .x((d) => xScale(d.x))  .y((d) => yScale(d.y))  .curve(d3.curveMonotoneX);  d3.select("#gfg")  .append("path")  .attr("d", line(data))  .attr("fill", "none")  .attr("stroke", "green");  </script> </body> </html>

Output:

Example 2: Sorting the unsorted points by the x-axis then rendering the curve.

html

<!DOCTYPE html> <html> <head> <meta charset="utf-8"> <script src= "https://cdnjs.cloudflare.com/ajax/libs/d3/4.2.2/d3.min.js">  </script> </head> <body> <h1 style="text-align:center; color:green;"> GeeksforGeeks </h1> <center> <svg id="gfg" width="250" height="200"></svg> </center> <script>  var points = [  {xpoint: 75, ypoint: 150},  {xpoint: 25, ypoint: 5},  {xpoint: 150, ypoint: 115},  {xpoint: 100, ypoint: 5},  {xpoint: 200, ypoint: 150}];  // Sorting the points by x axis  points.sort((a, b) => a.xpoint - b.xpoint);  var Gen = d3.line()  .x((p) => p.xpoint)  .y((p) => p.ypoint)  .curve(d3.curveMonotoneX);  d3.select("#gfg")  .append("path")  .attr("d", Gen(points))  .attr("fill", "none")  .attr("stroke", "green");  </script> </body> </html>