alpha-shapes aka concave hulls in d3

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>Alpha-Shapes</title>
    <script src="https://cdn.jsdelivr.net/npm/d3@2.10.3/d3.v2.js"></script>
    <script src="https://cdn.jsdelivr.net/npm/d3@12.10.3/d3.geom.js"></script>
    <style type="text/css">

path {
  stroke: #000;
  stroke-width: .5px;
  fill: #39c;
}

circle {
  fill: #39c;
}

</style>
  </head>
  <body>
    <script type="text/javascript">

var svg = d3.select("body")
  .append("svg")
    .attr("width", w)
    .attr("height", h)
    .attr("class", "Blues");

svg.append("g")
  .selectAll("circle")
    .data(vertices)
  .enter().append("circle")
    .attr("r", 3)
    .attr("cx", function(d) { return d[0]; })
    .attr("cy", function(d) { return d[1]; });
    
svg.append("g")
  .selectAll("path")
    .data(d3.geom.delaunay(offset(vertices,300,0)))
  .enter().append("path")
    .attr("d", function(d) { return "M" + d.join("L") + "Z"; });

svg.append("g")
  .selectAll("path")
    .data(mesh)
  .enter().append("path")
    .attr("d", function(d) { return "M" + d.join("L") + "Z"; });

</script>
  </body>
</html>

Modified http://mbostock.github.com/d3/d3.js to a secure url

Modified http://mbostock.github.com/d3/d3.geom.js to a secure url

https://mbostock.github.com/d3/d3.js

https://mbostock.github.com/d3/d3.geom.js