d3.js geoWagner6()用法及代碼示例

D3.js是一個JavaScript庫，用於在Web瀏覽器中生成動態的交互式數據可視化。它利用可伸縮矢量圖形，HTML5和級聯樣式表標準。

d3.js中的geoWagner6()函數用於繪製Wagner VI投影。

用法:

d3.geoWagner6()

參數：此方法不接受任何參數。

返回值：此方法根據給定的JSON數據創建並返回Wagner6投影。

範例1：以下示例對Wagner6進行投影，其中心為(0,0)，旋轉為0。

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:500px;">  
        <svg width="600" height="450">  
        </svg>  
    </div>  
      
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Wagner6 projection 
        // Center(0,0) with 0 rotation 
        var gfg = d3.geoWagner6() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([0,0]) 
            .center([0,0]) 
            .translate([width / 2, height / 2]); 
  
        // Loading the json data 
        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", "Seagreen") 
                    .attr("d", d3.geoPath() 
                        .projection(gfg) 
                    ) 
                    .style("stroke", "#ffff") 
        }); 
    </script> 
</body>  
  
</html>

輸出：

Wagner6世界的投影，無旋轉且以(0,0)為中心

範例2：下麵的示例在自定義中心和旋轉之後對世界進行Wagner6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:500px; height:600px;">  
        <svg width="500" height="450">  
        </svg>  
    </div>  
      
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Wagner6  projection 
        // Center(20,50) and 20 degree 
        // rotation w.r.t Y axis 
        var gfg = d3.geoWagner6() 
            .scale(width / 1.3 / Math.PI) 
            .rotate([0,20]) 
            .center([20,50]) 
            .translate([width / 2, height / 2]); 
  
        // Loading the json data 
        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", "SlateBlue") 
                    .attr("d", d3.geoPath() 
                        .projection(gfg) 
                    ) 
                    .style("stroke", "#ffff") 
        }); 
    </script> 
</body>  
  
</html>

輸出：

Wagner6投影，Y軸旋轉20度，並以(20,50)為中心

相關用法

注：本文由純淨天空篩選整理自jana_sayantan大神的英文原創作品 D3.js geoWagner6() Function。非經特殊聲明，原始代碼版權歸原作者所有，本譯文未經允許或授權，請勿轉載或複製。