D3.js density.bandwidth()函数

density.bandwidth()函数用于设置密度估计函数的带宽。如果未指定带宽，则它设置等于 20.4939 的默认带宽。如果指定了带宽，则它设置高斯内核的带宽并返回估计值。

句法：

d3.contourDensity.x().y().bandwidth([bandwidth]);

参数：此函数采用上面给出的一个参数，如下所述。

• 带宽：此函数采用一个数字，该数字定义了密度估计函数的带宽。

返回值：此函数不返回任何内容。

下面给出了density.bandwidth()函数的几个示例。

示例 1：

HTML

 
 
  
 
     
     
  
     
     
    
    
 
  
 
    GeeksforGeeks
      
     
        // append the svg object to the body.
        var svg = d3.select("body")
        .append("svg")
            .attr("width", 500)
            .attr("height", 500)
        .append("g")
            .attr("transform",
                "translate(" + 20 + ", " + -80 + ")");
  
        // read data
        d3.csv("./data.csv", function(data) {
              
        var y = d3.scaleLinear()
            .domain([-5, 30])
            .range([ 400, 100 ]);
  
        var x = d3.scaleLinear()
            .domain([0, 22])
            .range([ 0, 300]);
  
  
        svg.append("g")
        .call(d3.axisLeft(y));
          
        svg.append("g")
            .attr("transform", "translate(0, " + 400 + ")")
            .call(d3.axisBottom(x));
  
        var density= d3.contourDensity()
            .y(function(d) { return y(d.y); })
            .x(function(d) { return x(d.x); })
            // Use of bandwidth() Function
            .bandwidth(40)
            (data)
  
        svg.selectAll("path")
            .data(density)
            .enter()
            .append("path")
            .attr("d", d3.geoPath())
            .attr("fill", "none")
            .attr("stroke", "green")
        });
  
        // Data for csv file
        // x, y, group
        // 9.45, 4.4, H
        // 9.1, 4.4, H
        // 9.9, 9.9, H
        // 9.6, 4.5, H
        // 9.1, 9.7, H
        // 4.7, 9.5, H
        // 7.9, 9.6, H
        // 4.7, 9.7, H
        // 9.45, 4.4, H
        // 12.1, 9.4, H
        // 7.5, 9, H
        // 4.5, 4.5, H
        // 9.45, 9.7, H
        // 4.45, 9.6, H
        // 9.5, 7.6, H
        // 9, 9.45, H
        // 4.7, 12, H
        // 9.7, 9.7, H
        // 9.6, 9, H
        // 12, 9, H
        // 9.45, 4.5, H
        // 9.9, 4.6, H
        // 12.7, 9.9, H
        // 9, 12.4, H
        // 9, 4.9, H
        // 9.5, 9.7, H
        // 9.7, 4.7, H
        // 9.9, 4.5, H
        // 4, 4.5, H
        // 7.9, 9, H
        // 9.9, 9.45, H
        // 9, 4.4, H
        // 4.7, 9.7, H
        // 4.5, 9.9, H
     

输出：

示例 2：

HTML

 
 
  
 
     
     
  
     
     
    
    
 
  
 
    GeeksforGeeks
      
     
  
        // append the svg object to the body.
        var svg = d3.select("body")
        .append("svg")
            .attr("width", 500)
            .attr("height", 500)
        .append("g")
            .attr("transform",
                "translate(" + 20 + ", " + -80 + ")");
  
        // read data
        d3.csv("./data.csv", function(data) {
              
        var y = d3.scaleLinear()
            .domain([-5, 30])
            .range([ 400, 100 ]);
  
        var x = d3.scaleLinear()
            .domain([0, 22])
            .range([ 0, 300]);
  
  
        svg.append("g")
        .call(d3.axisLeft(y));
          
        svg.append("g")
            .attr("transform", "translate(0, " + 400 + ")")
            .call(d3.axisBottom(x));
  
        var density= d3.contourDensity()
            .y(function(d) { return y(d.y); })
            .x(function(d) { return x(d.x); })
            // Use of bandwidth() Function
            .bandwidth(10)
            (data)
  
        svg.selectAll("path")
            .data(density)
            .enter()
            .append("path")
            .attr("d", d3.geoPath())
            .attr("fill", "none")
            .attr("stroke", "green")
        });
  
        // Data for csv file
        // x, y, group
        // 9.45, 4.4, H
        // 9.1, 4.4, H
        // 9.9, 9.9, H
        // 9.6, 4.5, H
        // 9.1, 9.7, H
        // 4.7, 9.5, H
        // 7.9, 9.6, H
        // 4.7, 9.7, H
        // 9.45, 4.4, H
        // 12.1, 9.4, H
        // 7.5, 9, H
        // 4.5, 4.5, H
        // 9.45, 9.7, H
        // 4.45, 9.6, H
        // 9.5, 7.6, H
        // 9, 9.45, H
        // 4.7, 12, H
        // 9.7, 9.7, H
        // 9.6, 9, H
        // 12, 9, H
        // 9.45, 4.5, H
        // 9.9, 4.6, H
        // 12.7, 9.9, H
        // 9, 12.4, H
        // 9, 4.9, H
        // 9.5, 9.7, H
        // 9.7, 4.7, H
        // 9.9, 4.5, H
        // 4, 4.5, H
        // 7.9, 9, H
        // 9.9, 9.45, H
        // 9, 4.4, H
        // 4.7, 9.7, H
        // 4.5, 9.9, H
     

 

输出：