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D3.js geoWagner7() Function

  • Last Updated : 23 Sep, 2020
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D3.js is a JavaScript library for producing dynamic, interactive data visualizations in web browsers. It makes use of Scalable Vector Graphics, HTML5, and Cascading Style Sheets standards. 

The geoWagner7() function in d3.js is used to draw the Wagner VII projection.

Syntax: 

d3.geoWagner7()

Parameters: This method does not accept any parameters.

Return Value: This method creates Wagner7 projection from given JSON data.



Example 1: The following example makes the Wagner7 projection of the world with the center at (0,0) and 0 rotation.

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=
    </script>  
</head
  
<body
    <div style="width:700px; height:500px;"
        <svg width="600" height="450"
        </svg
    </div
      
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // Wagner7 projection
        // Center(0,0) with 0 rotation
        var gfg = d3.geoWagner7()
            .scale(width / 1.5 / Math.PI)
            .rotate([0,0])
            .center([0,0])
            .translate([width / 2, height / 2])
  
        // Loading the json 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", "BLACK")
                    .attr("d", d3.geoPath()
                        .projection(gfg)
                    )
                    .style("stroke", "#ffff")
        })
    </script>
</body
  
</html>

Output:

Wagner7 projection of World with no rotation and centered at (0,0)

Example 2: The following example makes the Wagner7 projection of the world after customizing the center and rotation.

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=
    </script>
</head
  
<body
    <div style="width:500px; height:600px;"
        <svg width="500" height="450"
        </svg
    </div
      
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // Wagner7  projection
        // Center(50,50) and 40 degree
        // rotation w.r.t Y axis
        var gfg = d3.geoWagner7()
            .scale(width / 1.3 / Math.PI)
            .rotate([40,0])
            .center([50,50])
            .translate([width / 2, height / 2])
  
        // Loading the json 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", "Grey")
                    .attr("d", d3.geoPath()
                    .projection(gfg)
                    )
                    .style("stroke", "#ffff")
        })
    </script>
</body
  
</html>

Output:

Wagner7 projection with 40-degree rotation w.r.t Y-axis and centered at (50,50)

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