D3.js geoGringorten() Function

Last Updated : 18 Sep, 2020

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 geoGringorten() function in d3.js is used to draw the Gringorten square equal-area projection, rearranged to give each hemisphere an entire square.

Syntax:

d3.geoGringorten()

Parameters: This method does not accept any parameters.

Return Value: This method creates Gringorten square equal-area projection. from given json data.

Example 1: The following example makes Gringorten projection of world with center at (0, 0) and no rotation.

<!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= 
"https://d3js.org/d3-geo-projection.v2.min.js"> 
    </script> 
</head> 
  
<body> 
    <div style="width:700px; height:500px;"> 
        <center> 
            <h3 style="color:black"></h3> 
        </center> 
        <svg width="600" height="450"></svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Gringorten projection 
        // Center(0, 0) with 0 rotation 
        var gfg = d3.geoGringorten() 
            .scale(width / 1.5 / 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 
        var myURL = "https://raw.githubusercontent.com/" 
            + "janasayantan/datageojson/master/world.json" 
  
        d3.json(myURL, function (data) { 
  
            // Draw the map 
            svg.append("g") 
                .selectAll("path") 
                .data(data.features) 
                .enter().append("path") 
                .attr("fill", "SlateBlue") 
                .attr("d", d3.geoPath() 
                    .projection(gfg) 
                ) 
                .style("stroke", "#ffff") 
        }) 
    </script> 
</body> 
  
</html> 

Output:

Gringorten projection with no rotation and centered at (0, 0)

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

<!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= 
"https://d3js.org/d3-geo-projection.v2.min.js"> 
    </script> 
</head> 
  
<body> 
    <div style="width:700px; height:600px;"> 
        <center> 
            <h3 style="color:black"></h3> 
        </center> 
        <svg width="700" height="400"> </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Gringorten  projection 
        // Center(-20, 20) and 90 degree 
        // rotation w.r.t Y axis 
        var gfg = d3.geoGringorten() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([90, 0]) 
            .center([-20, 20]) 
            .translate([width / 2, height / 2]) 
  
        // Loading the json data 
        // Used json file stored at: 
        // https://raw.githubusercontent.com/janasayantan 
        // /datageojson/master/world.json 
        var myURL = "https://raw.githubusercontent.com/" 
            + "janasayantan/datageojson/master/world.json" 
  
        d3.json(myURL, function (data) { 
  
            // Draw the map 
            svg.append("g") 
                .selectAll("path") 
                .data(data.features) 
                .enter().append("path") 
                .attr("fill", "SlateGrey") 
                .attr("d", d3.geoPath() 
                    .projection(gfg) 
                ) 
                .style("stroke", "#ffff") 
        }) 
    </script> 
</body> 
  
</html> 