D3.js geoEisenlohr() Function

Last Updated : 18 Sep, 2020

The JavaScript D3.js library provides interactive data visualizations for web page using HTML5, Scalable Vector Graphics, and Cascading Style Sheets. The geoEisenlohr() function in d3.js is used to draw the Eisenlohr conformal projection.

Syntax:

d3.geoEisenlohr()

Parameters: This method does not accept any parameters.

Returns: This method creates Eisenlohr projection from given JSON data.

Example 1: The following example creates Eisenlohr 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:600px;"> 
        <svg width="700" height="550"> 
        </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Eisenlohr  projection 
        // Center(0,0) and no rotation 
        var gfg = d3.geoEisenlohr() 
            .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> 
  
</html> 

Output:

Example 2: In following example we will create Eckert5 projection of world with center at (30, 0) and rotating 30 degree anti-clockwise with respect to Y axis.

<!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;"> 
        <svg width="700" height="550"> 
        </svg> 
    </div> 
  
    <script> 
        var svg = d3.select("svg"), 
            width = +svg.attr("width"), 
            height = +svg.attr("height"); 
  
        // Eisenlohr  projection 
        // Center(30, 0) and 30 degree rotation 
        var gfg = d3.geoEisenlohr() 
            .scale(width / 1.5 / Math.PI) 
            .rotate([-30, 0]) 
            .center([30, 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> 