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 geoMercator() function in d3.js is used to draw The equal-area, pseudo cylindrical Mollweide projection.
Syntax:
d3.geoMollweide()
Parameters: This method does not accept any parameters.
Returns: This method creates the Mollweide projection from given json data.
Example #1: The following example draws Mollweide projection of world with center at (0, 0) and 0 rotation.
<!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= </script> <script> var svg = d3.select("svg"), width = +svg.attr("width"), height = +svg.attr("height"); // Mollweide projection // Center(0, 0) with 0 rotation var gfg = d3 .geoMollweide() .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 /datageojson/master/world.json*/ d3.json( function (data) { // Drawing 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> |
Output:
Mollweide projection of World with no rotation and centered at (0, 0)
Example #2: The following example draws Mollweide projection of world after altering the center and rotation.
<!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= </script> <script> var svg = d3.select("svg"), width = +svg.attr("width"), height = +svg.attr("height"); // Mollweide projection // Center(0, 20) and 90 degree rotation w.r.t Y axis var gfg = d3 .geoMollweide() .scale(width / 1.7 / Math.PI) .rotate([90, 0]) .center([0, 20]) .translate([width / 2, height / 2]); // Loading the json data // Used json file stored at /datageojson/master/world.json*/ d3.json( function (data) { // Draw the map svg.append("g").selectAll( "path").data(data.features).enter().append( "path").attr("fill", "Sienna").attr( "d", d3.geoPath().projection(gfg)).style( "stroke", "#ffff"); }); </script> </body> </html> |
Output :
Mollweide projection with 90 degree rotation w.r.t Y axis and centered at (0, 20)
