d3.js geoGringorten()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geoGringorten()函數用於繪製Gringorten正方形equal-area投影，並重新排列以給每個半球一個完整的正方形。

用法:

d3.geoGringorten()

參數：此方法不接受任何參數。

返回值：此方法將創建Gringorten正方形equal-area投影。從給定的json數據。

範例1：以下示例對中心在(0，0)且沒有旋轉的世界進行Gringorten投影。

<!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;"> 
        <center> 
            <h3 style="color:black"></h3> 
        </center> 
        <svg width="600" height="450"></svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Gringorten projection 
        // Center(0, 0) with 0 rotation 
        var gfg = d3.geoGringorten() 
            .scale(width / 1.5 / 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 
        var myURL = "https://raw.githubusercontent.com/" 
            + "janasayantan/datageojson/master/world.json" 
  
        d3.json(myURL, 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：

Gringorten投影，不旋轉，並以(0，0)為中心

範例2：以下示例在自定義中心和旋轉之後製作了Gringorten世界投影。

<!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="700" height="400"> </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Gringorten  projection 
        // Center(-20, 20) and 90 degree 
        // rotation w.r.t Y axis 
        var gfg = d3.geoGringorten() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([90, 0]) 
            .center([-20, 20]) 
            .translate([width / 2, height / 2]) 
  
        // Loading the json data 
        // Used json file stored at:
        // https://raw.githubusercontent.com/janasayantan 
        // /datageojson/master/world.json 
        var myURL = "https://raw.githubusercontent.com/" 
            + "janasayantan/datageojson/master/world.json" 
  
        d3.json(myURL, function (data) { 
  
            // Draw the map 
            svg.append("g") 
                .selectAll("path") 
                .data(data.features) 
                .enter().append("path") 
                .attr("fill", "SlateGrey") 
                .attr("d", d3.geoPath() 
                    .projection(gfg) 
                ) 
                .style("stroke", "#ffff") 
        }) 
    </script> 
</body> 
  
</html>

輸出：

Y軸旋轉90度旋轉的Gringorten投影，其中心位於(-20，20)

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 geoGringorten() 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。