D3.js contourDensity() Function

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The d3.contourDensity() function is used to construct a new density estimator function with the default settings. A density estimator function estimates the density for the given set of data.

Syntax:

d3.contourDensity();

Parameters: This function does not take any parameters.

Return Value: This function returns a function.

Below given are a few examples of the function given above.

Example 1:

<!DOCTYPE html>  
<html lang="en">  
<head>  
    <meta charset="UTF-8">  
    <meta name="viewport" content="  
    width=device-width, initial-scale=1.0">  
  
    <script type="text/javascript"
    src="https://d3js.org/d3.v4.min.js">  
    </script>  
    <script src="https://d3js.org/d3-contour.v1.min.js"> 
    </script> 
</head>  
<body>  
    <h1 style="color:green">zambiatek</h1> 
      
    <script>  
        // append the svg object to the body. 
        var svg = d3.select("body") 
        .append("svg") 
        .attr("width", 530) 
        .attr("height", 480) 
        .append("g") 
        .attr("transform", 
        "translate(" + 40 + ", " + 0 + ")"); 
  
        // Read data 
        d3.csv("./data.csv", function(data) { 
              
            var y = d3.scaleLinear() 
            .domain([5, 30]) 
            .range([ 450, 10 ]); 
  
            var x = d3.scaleLinear() 
            .domain([5, 22]) 
            .range([ 0, 460]); 
  
  
            svg.append("g") 
            .call(d3.axisLeft(y)); 
          
            svg.append("g") 
            .attr("transform","translate(0, " + 450 + ")") 
            .call(d3.axisBottom(x)); 
  
            var densityData = d3.contourDensity() 
            .y(function(d) { return y(d.y); }) 
            .x(function(d) { return x(d.x); })(data) 
  
            svg.selectAll("path") 
            .data(densityData) 
            .enter() 
            .append("path") 
            .attr("d", d3.geoPath()) 
            .attr("fill", "none") 
            .attr("stroke", "green") 
        }); 
  
        // Data for csv file 
        // x, y, group 
        // 11.45, 14.2, H 
        // 11.1, 14.2, H 
        // 11.9, 9.9, H 
        // 11.6, 14.5, H 
        // 11.1, 11.7, H 
        // 14.7, 9.5, H 
        // 7.9, 11.6, H 
        // 14.7, 11.7, H 
        // 11.45, 14.2, H 
        // 12.1, 9.2, H 
        // 7.5, 11, H 
        // 14.5, 14.5, H 
        // 11.45, 9.7, H 
        // 14.45, 11.6, H 
        // 11.5, 7.6, H 
        // 11, 11.45, H 
        // 14.7, 12, H 
        // 11.7, 9.7, H 
        // 9.6, 9, H 
        // 12, 11, H 
        // 11.45, 14.5, H 
        // 11.11, 14.6, H 
        // 12.7, 11.11, H 
        // 11, 12.2, H 
        // 11, 14.9, H 
        // 9.5, 11.7, H 
        // 11.7, 14.7, H 
        // 11.9, 14.5, H 
        // 14, 14.5, H 
        // 7.11, 11, H 
        // 11.11, 11.45, H 
        // 11, 14.2, H 
        // 14.7, 11.7, H 
        // 14.5, 11.9, H 
    </script>  
</body>  
</html>  

Output:

Example 2:

<!DOCTYPE html>  
<html lang="en">  
<head>  
    <meta charset="UTF-8">  
    <meta name="viewport" content="  
    width=device-width, initial-scale=1.0">  
  
    <script type="text/javascript"
    src="https://d3js.org/d3.v4.min.js">  
    </script>  
    <script src="https://d3js.org/d3-contour.v1.min.js"> 
    </script> 
</head>  
  
<body>  
    <h1 style="color:green">zambiatek</h1> 
      
    <script>  
        // Append the svg object to the body. 
        var svg = d3.select("body") 
        .append("svg") 
        .attr("width", 530) 
        .attr("height", 480) 
        .append("g") 
        .attr("transform", 
        "translate(" + 40 + ", " + 0 + ")"); 
  
        // Read data 
        d3.csv("./data.csv", function(data) { 
              
            var y = d3.scaleLinear() 
            .domain([5, 30]) 
            .range([ 450, 10 ]); 
  
            var x = d3.scaleLinear() 
            .domain([5, 22]) 
            .range([ 0, 460]); 
  
            svg.append("g") 
            .call(d3.axisLeft(y)); 
          
            svg.append("g") 
            .attr("transform","translate(0, " + 450 + ")") 
            .call(d3.axisBottom(x)); 
  
            var densityData = d3.contourDensity() 
            .y(function(d) { return y(d.y); }) 
            .bandwidth(44) 
            .x(function(d) { return x(d.x); })(data) 
  
            svg.selectAll("path") 
            .data(densityData) 
            .enter() 
            .append("path") 
            .attr("d", d3.geoPath()) 
            .attr("fill", "green") 
            .attr("stroke", "black") 
        }); 
  
        // Data for csv file 
        // x, y, group 
        // 11.45, 14.2, H 
        // 11.1, 14.2, H 
        // 11.9, 9.9, H 
        // 11.6, 14.5, H 
        // 11.1, 11.7, H 
        // 14.7, 9.5, H 
        // 7.9, 11.6, H 
        // 14.7, 11.7, H 
        // 11.45, 14.2, H 
        // 12.1, 9.2, H 
        // 7.5, 11, H 
        // 14.5, 14.5, H 
        // 11.45, 9.7, H 
        // 14.45, 11.6, H 
        // 11.5, 7.6, H 
        // 11, 11.45, H 
        // 14.7, 12, H 
        // 11.7, 9.7, H 
        // 9.6, 9, H 
        // 12, 11, H 
        // 11.45, 14.5, H 
        // 11.11, 14.6, H 
        // 12.7, 11.11, H 
        // 11, 12.2, H 
        // 11, 14.9, H 
        // 9.5, 11.7, H 
        // 11.7, 14.7, H 
        // 11.9, 14.5, H 
        // 14, 14.5, H 
        // 7.11, 11, H 
        // 11.11, 11.45, H 
        // 11, 14.2, H 
        // 14.7, 11.7, H 
        // 14.5, 11.9, H 
    </script>  
</body>  
</html>  

Output:

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