D3.js geoEckert4() 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 geoEckert4() function in d3.js is used to draw the Eckert IV projection which is an equal-area pseudocylindrical map projection. The length of the polar lines is half that of the equator, and lines of longitude are semi ellipses or portions of ellipses.

Syntax:

d3.geoEckert4()

Parameters: This method does not accept any parameters.

Return Value: This method creates an Eckert4 projection from given JSON data.



Example 1: The following example makes Eckert4 projection of the world with the center at (0,0) and no rotation.

HTML

filter_none

edit
close

play_arrow

link
brightness_4
code

<!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:600px;"
        <svg width="700" height="550"
        </svg
    </div
      
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // geoEckert Iv  projection
        // Center(0,0) and no rotation
        var gfg = d3.geoEckert4()
            .scale(width / 1.5 / Math.PI)
            .rotate([0,0])
            .center([0,0])
            .translate([width / 2, height / 2])
  
        // Loading the json data
        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>

chevron_right


Output :

Eckert IV Projection with (0,0) center and 0 rotation

Example 2: The following example makes Eckert4 projection of the world with the center at (0,0) and 20-degree Rotation clockwise.

HTML

filter_none

edit
close

play_arrow

link
brightness_4
code

<!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:600px;"
        <center
            <h3 style="color:black"
            Eckert IV Projection of World
            </h3>  
        </center>
        <svg width="700" height="400"
        </svg
    </div
      
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");
  
        // geoEckert IV  projection
        // Center(0,0) and rotating 20 
        // degree clockwise
        var gfg = d3.geoEckert4()
            .scale(width / 1.5 / Math.PI)
            .rotate([20,0])
            .center([0,0])
            .translate([width / 2, height / 2])
  
        // Loading the json data
        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>

chevron_right


Output:

Eckert IV Projection with rotation

full-stack-img




My Personal Notes arrow_drop_up

Check out this Author's contributed articles.

If you like GeeksforGeeks and would like to contribute, you can also write an article using contribute.geeksforgeeks.org or mail your article to contribute@geeksforgeeks.org. See your article appearing on the GeeksforGeeks main page and help other Geeks.

Please Improve this article if you find anything incorrect by clicking on the "Improve Article" button below.


Article Tags :

Be the First to upvote.


Please write to us at contribute@geeksforgeeks.org to report any issue with the above content.