d3.js geoNellHammer()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geoNellHammer()函数用于绘制Nell-Hammer投影。

用法:

d3.geoNellHammer()

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Nell-Hammer投影。

范例1：下面的示例创建中心为(0，0)且不旋转的Nell-Hammer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" 
        /> 
    </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"); 
  
             // Nell-Hammer projection 
             // Center(0,0) with 0 rotation 
             var gfg = d3.geoNellHammer() 
             .scale(width / 1.8 / 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", "DarkSlateBlue") 
                   .attr("d", d3.geoPath() 
                   .projection(gfg) 
                   ) 
                   .style("stroke", "#ffff") 
            }) 
        </script> 
    </body> 
</html>

输出：

范例2：在以下示例中，我们将创建中心为(0，20)且相对于Y轴旋转-45度的世界的Nell-Hammer投影。

<!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:600px;"> 
            <center> 
                <h3 style="color:black;"></h3> 
            </center> 
  
            <svg width="500" 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"); 
  
            // NellHammer  projection 
     // Center(0,20) and -45 degree rotation w.r.t Y axis 
            var gfg = d3 
                .geoNellHammer() 
                .scale(width / 1.7 / Math.PI) 
                .rotate([-45, 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", "DarkTurquoise").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 geoNellHammer() 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。