Saturday, February 7, 2026
HomeLanguagesJavascriptD3.js geoFahey() Function

D3.js geoFahey() Function

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 geoFahey() function in d3.js is used to draw the Fahey pseudo cylindrical projection.

Syntax:

d3.geoFahey()

Parameters: This method does not accept any parameters.

Return Value: This method creates Fahey pseudo cylindrical projection from given json data.

Example 1: The following example makes Eckert6 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=
    </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");
  
        // Fahey  projection
        // Center(0,0) with 0 rotation
        var gfg = d3.geoFahey()
            .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", "DarkBlue")
                    .attr("d", d3.geoPath()
                        .projection(gfg)
                    )
                    .style("stroke", "#ffff")
            })
    </script>
</body>
  
</html>


Output:

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

Example 2: The following example makes Fahey 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=
    </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");
  
        // Fahey  projection
        // Center(0,10) and 45 degree 
        // anticlock rotation
        var gfg = d3.geoFahey()
            .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", "DarkOliveGreen")
                    .attr("d", d3.geoPath()
                        .projection(gfg)
                    )
                    .style("stroke", "#ffff")
            })
    </script>
</body>
  
</html>


Output:

Fahey projection with 45 degree anti-clock rotation and centered at (0,10)

Whether you’re preparing for your first job interview or aiming to upskill in this ever-evolving tech landscape, neveropen Courses are your key to success. We provide top-quality content at affordable prices, all geared towards accelerating your growth in a time-bound manner. Join the millions we’ve already empowered, and we’re here to do the same for you. Don’t miss out – check it out now!
RELATED ARTICLES

1 COMMENT

Most Popular

Dominic
32493 POSTS0 COMMENTS
Milvus
126 POSTS0 COMMENTS
Nango Kala
6864 POSTS0 COMMENTS
Nicole Veronica
11990 POSTS0 COMMENTS
Nokonwaba Nkukhwana
12083 POSTS0 COMMENTS
Shaida Kate Naidoo
7000 POSTS0 COMMENTS
Ted Musemwa
7241 POSTS0 COMMENTS
Thapelo Manthata
6951 POSTS0 COMMENTS
Umr Jansen
6936 POSTS0 COMMENTS