D3.js geoMtFlatPolarParabolic()函数

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geoMtFlatPolarParabolic ()函数用于绘制McBryde-Thomas平极抛物线伪圆柱等面积投影。

句法：

d3.geoMtFlatPolarParabolic()

参数：此方法不接受任何参数。

返回：此方法从给定的 JSON 数据创建 McBryde-Thomas 平极抛物线伪圆柱等面积投影。

示例 #1：以下示例创建世界的 MtFlatPolarParabolic 投影，中心在 (0, 0) 并且没有旋转。

    
        
        
    
  
    
        
            
                
            
  
            
        
        
        
      
        
            var svg = d3.select("svg"),
                width = +svg.attr("width"),
                height = +svg.attr("height");
  
            // MtFlatPolarParabolic projection
            // Center(0, 0) with 0 rotation
            var gfg = d3
                .geoMtFlatPolarParabolic()
                .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");
            });
        
    

输出：

示例 2：在下面的示例中，我们将创建世界的 MtFlatPolarParabolic 投影，中心位于 (0, 20) 并相对于 Y 轴旋转 90 度。

    
        
        
    
  
    
        
            
                
            
  
            
        
        
        
      
        
            var svg = d3.select("svg"),
                width = +svg.attr("width"),
                height = +svg.attr("height");
  
            // MtFlatPolarParabolic  projection
         // Center(0, 20) and 90 degree rotation w.r.t Y axis
            var gfg = d3
                .geoMtFlatPolarParabolic()
                .scale(width / 1.7 / Math.PI)
                .rotate([90, 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", "DodgerBlue").attr(
                  "d", d3.geoPath().projection(gfg)).style(
                  "stroke", "#ffff");
            });
        
    

输出 ：