d3.js geoEisenlohr()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geoEisenlohr()函数用于绘制艾森洛尔共形投影。

用法:

d3.geoEisenlohr()

参数：此方法不接受任何参数。

返回：此方法根据给定的JSON数据创建Eisenlohr投影。

范例1：以下示例创建中心为(0，0)且不旋转的世界的艾森洛尔投影。

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;"> 
        <svg width="700" height="550"> 
        </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Eisenlohr  projection 
        // Center(0,0) and no rotation 
        var gfg = d3.geoEisenlohr() 
            .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 
        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", "black") 
                    .attr("d", d3.geoPath() 
                        .projection(gfg) 
                    ) 
                    .style("stroke", "#ffff") 
            }) 
    </script> 
  
</html>

输出：

范例2：在下面的示例中，我们将创建Eckert5投影，该投影的中心为(30，0)，并且相对于Y轴旋转30度anti-clockwise。

<!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;"> 
        <svg width="700" height="550"> 
        </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Eisenlohr  projection 
        // Center(30, 0) and 30 degree rotation 
        var gfg = d3.geoEisenlohr() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([-30, 0]) 
            .center([30, 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) { 
                // Draw 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：

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 geoEisenlohr() 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。