D3.js area.y1() method

Last Updated : 07 Sep, 2020

The d3.area.y1() method is used to set the y1 accessor to the argument passed to it which may be either a number or a function that returns a number, this is the second point or our upper bounds.

Syntax:

d3.area.y1(y1_point)

Parameters: This function accepts a single parameter as mentioned above and described below.

y1_point: This parameter is a number lower bound point or a function that returns a number.

Return Value: This method returns no value.

Example 1:

<!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> 
  
    <h3 style="text-align: center;"> 
        D3.js | d3.area.y1() Method 
    </h3> 
  
    <center> 
        <svg id="gfg" width="200" height="200"> 
        </svg> 
    </center> 
  
    <script> 
        var data = [ 
          {x: 50, y: 10}, 
          {x: 150, y: 30}, 
          {x: 200, y: 150}, 
          {x: 250, y: 10}, 
          {x: 300, y: 150}, 
          {x: 350, y: 50}, 
          {x: 400, y: 190}]; 
  
        var xScale =  
d3.scaleLinear().domain([0, 8]).range([25, 200]); 
        var yScale =  
d3.scaleLinear().domain([0, 20]).range([200, 25]); 
  
        var Gen = d3.area() 
          .x((p) => p.x) 
          .y0((p) => p.y*2) 
          // Using area.y1() method 
          .y1((p) => p.y*4); 
  
        d3.select("#gfg") 
          .append("path") 
          .attr("d", Gen(data)) 
          .attr("fill", "green") 
          .attr("stroke", "black"); 
    </script> 
</body> 
  
</html>

Output:

Example 2:

<!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> 
  
    <h3 style="text-align: center;"> 
        D3.js | d3.area.y1() Method 
    </h3> 
  
    <center> 
        <svg id="gfg" width="250" height="200"> 
    </svg> 
    </center> 
  
    <script> 
        var points = [ 
          {xpoint: 25,  ypoint: 150}, 
          {xpoint: 75,  ypoint: 50}, 
          {xpoint: 100, ypoint: 150}, 
          {xpoint: 100, ypoint: 50}, 
          {xpoint: 200, ypoint: 150}]; 
  
  
        var Gen = d3.area() 
          .x((p) => p.xpoint) 
          .y0((p) => p.ypoint/2) 
          // Setting upper bounds 
          .y1((p) => p.ypoint); 
  
        d3.select("#gfg") 
          .append("path") 
          .attr("d", Gen(points)) 
          .attr("fill", "green") 
          .attr("stroke", "black"); 
  
    </script> 
</body> 
  
</html>