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                <svg viewBox="0 0 960 600">
  <!--  we'll put SVG <path> elements here with D3js -->

  Blog post:
  <a href="" target="_blank">
    "Get Started Creating D3 Maps"

  Canvas version:
  <a href="" target="_blank">

<script src=""></script>
<script src=""></script>


                body {
  margin: 5px;
  text-align: center;
  background-color: #007da4;

svg {
  width: calc(100vmin - 10px);
  outline: 1px solid white;
  stroke-linejoin: round;
  stroke-linecap: round;

path.feature {
  stroke-width: 1px;
  stroke: white;
  fill: none;

p, a {
  color: white;
  font-family: sans-serif;
  font-size: 0.8rem;



                // make D3 aware of the <svg> element in the HTML
var svg ="svg");

// get <svg> width and height from HTML instead of hard-coding values
var svgWidth = +svg.attr("viewBox").split(" ")[2],
  svgHeight = +svg.attr("viewBox").split(" ")[3];

// define the map projection
// we're going from spherical latitude/longitude coordinates to a flat map
var projection = d3
  // use Mercator for now, sigh, because of web map ubiquity...
  // shift the projection translation offset to half of the parent <svg> width and height
  .translate([svgWidth / 2, svgHeight / 2])
  // [0, 0] is redundant, but you could change the initial center [longitude, latitude]
  .center([0, 0])
  // [0, 0, 0] is also redundant, but you can change the rotation along 3 axes
  // this property is really fun, so experiment with different values!
  .rotate([0, 0, 0])
  // set an initial scale value
  .scale(svgWidth / (2 * Math.PI));

// NOTE: if you want to skip setting the translate and scale values
// and instead zoom out to the whole world, you can just use this shortcut:
// projection.fitSize([svgWidth, svgHeight], {
//   type: "Sphere"
// });

// "d3.geoPath" helps convert from geojson coordinates to <svg> or <canvas> drawing instructions
// it needs to know about the projection that was defined above

// I like to refer to it as a "geographic path generator" throughout the code
var geoPathGenerator = d3.geoPath().projection(projection);

// request publicly available and hosted world topojson data,
// convert it to geojson,
// and then draw it in the <svg>
  .then(function(loadedTopoJson) {
    // use the concept of a topojson "mesh" to convert topojson
    // to a single, efficient geojson geometry
    var geoJson = topojson.mesh(

    // and then draw the single geojson representing all country polygons
    // as a single <path> element within the <svg> parent element
    // (1 geojson geometry results in only 1 <path> element)
      .attr("d", geoPathGenerator(geoJson))
      .attr("class", "feature");

    // an alternate and very common approach is to convert the topojson to a geojson feature collection,
    // where each country polygon is represented by an individual geojson feature
    // and thus each geojson feature is drawn as a unique <path> element within the <svg> parent element    
    // RESULT:
    // many geojson features resulting in as many <path> elements

    // WHY?
    // this is useful for thematic mapping

    // HOW?
    // you can uncomment the code below and try it out

    // var geoJson = topojson.feature(loadedTopoJson,;

    // svg
    //   .selectAll("path")
    //   .data(geoJson.features)
    //   .enter()
    //   .append("path")
    //   .attr("d", geoPathGenerator)
    //   .attr("class", "feature");