D3.js geoCraster() Function

Last Updated : 23 Sep, 2020

The geoCraster() function in d3.js is used to draw the Craster parabolic projection of the given geojson data. A Craster parabolic projection is also known as Putniņš P4.

Syntax:

d3.geoCraster()

Parameters: This method does not accept any parameters.

Return Value: This method returns the Craster projection.

Example 1: The following example draws the Craster projection of the world with the center at (0, 0) and a rotation of 0 degrees.

HTML

<!DOCTYPE html>
<html>

<head>
    <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;">
        <center>
            <h3 style="color:black"></h3>
        </center>
        <svg width="600" height="450">
        </svg>
    </div>
    
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");

        // Craster projection
        // Center at (0,0) with 0 degrees
        // rotation
        var gfg = d3.geoCraster()
            .scale(width / 1.8 / 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) {

                // Drawing 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:

Example 2: The following example draws the Craster projection of the world with the center at (0, 20) and a rotation of -45 degrees with respect to the y-axis.

HTML

<!DOCTYPE html>
<html>

<head>
    <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;">
        <center>
            <h3 style="color:black"></h3>
        </center>
        <svg width="500" height="450">
        </svg>
    </div>
    
    <script>
        var svg = d3.select("svg"),
            width = +svg.attr("width"),
            height = +svg.attr("height");

        // Craster  projection
        // Center(0,20) and -45 degree
        // rotation w.r.t y-axis
        var gfg = d3.geoCraster()
            .scale(width / 1.8 / Math.PI)
            .rotate([-45, 0])
            .center([0, 20])
            .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>

Output:

D3.js geoCraig() Function

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D3.js geoCraster() Function

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