D3.js geoAzimuthalEquidistant()函数

d3.js 中的geoAzimuthalEquidistant ()函数用于从给定的geojson数据中绘制方位角等距投影。这是一种地图投影，其中地图上的所有点都按比例与中心点保持正确的距离。此外，地图上的所有点都位于中心点的正确方向。

句法：

d3.geoAzimuthalEquidistant()

参数：此方法不接受任何参数。

返回值：此方法返回方位角等距投影。

示例 1：以下示例绘制方位角等距 以 (0,0) 为中心的世界投影。

HTML

  

    
    
    
    

  

    
        
            
                AzimuthalEquidistant Projection
                of World
            
        
        
        
    
    
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // AzimuthalEquidistant projection
        var gfg = d3.geoAzimuthalEquidistant()
            .scale(width / 1.5 / Math.PI)
            .translate([width / 2, height / 2]);
  
        // Loading the geojson 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", "Silver")
                    .attr("d", d3.geoPath()
                        .projection(gfg)
                    )
                    .style("stroke", "#ffff")
            });
    

  

输出：

示例 2：以下示例使方位角等距投影以 (-10,0) 为中心并相对于 x 轴逆时针旋转 10 度。

HTML

  

    
    
    
    

  

    
        
            
                AzimuthalEquidistant Projection
                of World
            
        
        
        
    
    
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // AzimuthalEquidistant  projection
        // Center(0,-10) and roating -10 degree
        var gfg = d3.geoAzimuthalEquidistant()
            .scale(width / 1.5 / Math.PI)
            .rotate([-10, 0])
            .center([0, -10])
            .translate([width / 2, height / 2]);
  
        // Loading the geojson 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", "green")
                    .attr("d", d3.geoPath()
                        .projection(gfg)
                    )
                    .style("stroke", "#ffff")
            });
    

  

输出：