D3.js geoCylindricalEqualArea() Function

Last Updated : 07 Feb, 2022

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 CylindricalEqualArea() function in d3.js is used to draw The cylindrical equal-area projection.

Syntax:

d3.geoCylindricalEqualArea()

Parameters: This method does not accept any parameters.

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

Example 1: The following example draws CylindricalEqualArea projection of world with 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" />
</head>
 
<body>
    <div style="width: 700px; height: 500px;">
        <center>
            <h3 style="color: black;"></h3>
        </center>
 
        <svg width="600" height="450"></svg>
    </div>
    <script src="https://d3js.org/d3.v4.js"></script>
    <script src=
    "https://d3js.org/d3-geo-projection.v2.min.js">
    </script>
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
 
        // CylindricalEqualArea projection
        // Center(0, 0) with 0 rotation
        var gfg = d3
            .geoCylindricalEqualArea()
            .scale(width / 1.8 / 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) {
                // Drawing the map
                svg.append("g").selectAll(
                    "path").data(data.features).enter().append(
                        "path").attr("fill", "GoldenRod").attr(
                            "d", d3.geoPath().projection(gfg)).style(
                                "stroke", "#ffff");
            });
    </script>
</body>
 
</html>

Output:

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

Example 2: The following example draws CylindricalEqualArea projection of world after altering 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" />
</head>
 
<body>
    <div style="width: 700px; height: 600px;">
        <center>
            <h3 style="color: black;"></h3>
        </center>
 
        <svg width="500" height="450"></svg>
    </div>
    <script src="https://d3js.org/d3.v4.js"></script>
    <script src=
    "https://d3js.org/d3-geo-projection.v2.min.js">
    </script>
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
 
        // CylindricalEqualArea  projection
        // Center(0, 20) and 45 degree rotation w.r.t Y axis
        var gfg = d3
            .geoCylindricalEqualArea()
            .scale(width / 1.8 / Math.PI)
            .rotate([45, 0])
            .center([0, 20])
            .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", "SaddleBrown").attr(
                            "d", d3.geoPath().projection(gfg)).style(
                                "stroke", "#ffff");
            });
    </script>
</body>
 
</html>