D3.js geoEquirectangular() Function

Last Updated : 23 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 geoEquirectangular() function in d3.js is used to draw the equirectangular projection which is a simple map projection attributed to Marinus of Tyre, who Ptolemy claims invented the projection.

Syntax:

d3.geoEquirectangular()

Parameters: This method does not accept any parameters.

Return Value: This method creates an Equirectangular projection from given json data.

Example 1: The following example makes Equirectangular projection of world with center at (0,0) and no 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="https://d3js.org/d3-geo-projection.v2.min.js"> 
    </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"); 
  
        // Equirectangular  projection 
        // Center(0,0) and no rotation 
        var gfg = d3.geoEquirectangular() 
            .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 
        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:

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

Example 2: The following example makes Equirectangular projection of world with changing 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="https://d3js.org/d3-geo-projection.v2.min.js"></script> 
</head> 
  
<body> 
    <div style="width:700px; height:900px;"> 
        <svg width="400" height="450"> 
        </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Equirectangular  projection 
        // Center(0,10) and 45 degree  
        // anticlock rotation 
        var gfg = d3.geoEquirectangular() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([45, 0]) 
            .center([0, 10]) 
            .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", "grey") 
                    .attr("d", d3.geoPath() 
                        .projection(gfg) 
                    ) 
                    .style("stroke", "#ffff") 
            }) 
    </script> 
</body> 
  
</html> 