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d3.js geoAiry()用法及代码示例

d3.js中的geoAiry()函数用于根据给定的geojson数据绘制艾里的minimum-error方位角投影。这是对由于Map投影最小化而导致的形状和面积误差的解决方案。

用法:

d3.geoAiry()

参数:此方法不接受任何参数。

返回值:此方法返回艾里的minimum-error方位角投影。

范例1:以下示例绘制了Airy的亚洲minimum-error方位角投影。



HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <script src="https://d3js.org/d3.v4.min.js"> 
    </script> 
    <script src= 
"https://d3js.org/d3-geo-projection.v2.min.js"> 
    </script> 
</head> 
  
<body> 
    <div style="width:1200px; height:1000px;"> 
        <center> 
            <h3 style="color:green"> 
                geoAiry Projection of Asia 
            </h3> 
        </center> 
        <svg width="800" height="500"> 
        </svg> 
    </div> 
    <svg width="400" height="300"></svg> 
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // geoAiry projection 
        var gfg = d3.geoAiry() 
            .scale(width / 1.5 / Math.PI) 
            .translate([width / 2, height / 2]); 
  
        // Loading the json data 
        d3.json("https://raw.githubusercontent.com/" + 
            "janasayantan/datageojson/master/" + 
            "geoasia.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:

范例2:以下示例绘制了Airy的minimum-error世界方位角投影。

HTML

<!DOCTYPE html> 
<html> 
  
<head> 
    <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:grey"> 
                azimuthal Projection of World 
            </h3> 
        </center> 
        <svg width="700" height="550"> 
        </svg> 
    </div> 
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // geoAiry projection 
        var gfg = d3.geoAiry() 
            .scale(width / 1.5 / Math.PI) 
            .translate([width / 2, height / 2]); 
  
        // Loading the json data 
        d3.json("https://raw.githubusercontent.com/" + 
            "janasayantan/datageojson/master/" + 
            "geoworld%20.json", 
            function (data) { 
  
                // Draw the map 
                svg.append("g") 
                    .selectAll("path") 
                    .data(data.features) 
                    .enter().append("path") 
                    .attr("fill", "green") 
                    .attr("d", d3.geoPath() 
                        .projection(gfg) 
                    ) 
                    .style("stroke", "#ffff"); 
            }); 
    </script> 
</body> 
  
</html>

输出:




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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 geoAiry() Function。非经特殊声明,原始代码版权归原作者所有,本译文的传播和使用请遵循“署名-相同方式共享 4.0 国际 (CC BY-SA 4.0)”协议。