d3.js geoPatterson()用法及代码示例

JavaScript D3.js库使用HTML5，可缩放矢量图形和级联样式表为网页提供交互式数据可视化。 d3.js中的geoPatterson()函数用于绘制Patterson圆柱投影。

用法：

d3.geoPatterson()

参数：此方法不接受任何参数。

返回值：此方法根据给定的JSON数据创建Patterson圆柱投影。

范例1：以下示例创建中心为(0，0)且不旋转的世界的帕特森投影。

HTML

<!DOCTYPE html>  
<html lang="en">  
  
<head>  
    <meta charset="UTF-8" />  
    <meta name="viewport"
        content="width=device-width,  
                initial-scale=1.0"/>  
</head>  
<body>  
    <div style="width:700px; height:500px;">  
        <center>   
            <h3 style="color:black"></h3>   
        </center> 
          
        <svg width="600" height="450">  
        </svg>  
    </div>  
    <script src="https://d3js.org/d3.v4.js"></script> 
    <script src= 
"https://d3js.org/d3-geo-projection.v2.min.js"> 
    </script> 
  
    <script> 
  
        var svg = d3.select("svg"), 
        width = +svg.attr("width"), 
        height = +svg.attr("height"); 
  
        // Patterson projection 
        // Center(0,0) with 0 rotation 
        var gfg = d3.geoPatterson() 
                   .scale(width / 2.4 / Math.PI) 
                 .rotate([0,0]) 
                 .center([0,0]) 
                 .translate([width / 2, height / 2]) 
  
        // Loading the json data 
        // Used json file stored at  
        // https://raw.githubusercontent.com/janasayantan 
        // /datageojson/master/world.json 
        d3.json("https://raw.githubusercontent.com/" 
            + "janasayantan/datageojson/master/world.json",  
            function(data){ 
  
           // Drawing the map 
           svg.append("g") 
              .selectAll("path") 
              .data(data.features) 
              .enter().append("path") 
              .attr("fill", "Black") 
              .attr("d", d3.geoPath() 
                   .projection(gfg) 
               ) 
              .style("stroke", "#ffff") 
        }) 
    </script> 
</body> 
   
</html>

输出：

范例2：在下面的示例中，我们将创建中心为(0，-20)且相对于Y轴旋转90度的世界的Patterson投影。

HTML

<!DOCTYPE html>  
<html lang="en">  
  
<head>  
    <meta charset="UTF-8" />  
    <meta name="viewport"
        content="width=device-width,  
                initial-scale=1.0"/>  
    <script src="https://d3js.org/d3.v4.js"></script> 
    <script src= 
"https://d3js.org/d3-geo-projection.v2.min.js"> 
    </script> 
</head>  
  
<body>  
    <div style="width:700px; height:600px;">  
        <center>  
            <h3 style="color:black"></h3>   
        </center> 
        <svg width="500" height="450">  
        </svg>  
    </div>  
  
    <script> 
  
        var svg = d3.select("svg"), 
        width = +svg.attr("width"), 
        height = +svg.attr("height"); 
  
        // Patterson  projection 
        // Center(0,-20) and 90 degree 
        // rotation w.r.t Y axis 
        var gfg = d3.geoPatterson() 
                 .scale(width / 1.7 / Math.PI) 
                 .rotate([90,0]) 
                 .center([0,-20]) 
                 .translate([width / 2, height / 2]) 
  
       // Loading the json data 
       // Used json file stored at https:
       //raw.githubusercontent.com/janasayantan 
       // /datageojson/master/world.json 
       d3.json("https://raw.githubusercontent.com/janasayantan/" 
               +"datageojson/master/world.json", function(data){ 
  
              // Draw the map 
              svg.append("g") 
                 .selectAll("path") 
                 .data(data.features) 
                 .enter().append("path") 
                 .attr("fill", "grey") 
                 .attr("d", d3.geoPath() 
                       .projection(gfg) 
                 ) 
                 .style("stroke", "#ffff") 
        }) 
    </script> 
</body>  
  
</html>

输出：

相关用法

注：本文由纯净天空筛选整理自jana_sayantan大神的英文原创作品 D3.js geoPatterson() Function。非经特殊声明，原始代码版权归原作者所有，本译文未经允许或授权，请勿转载或复制。