CartoDB + D3 Bubble Map

<!DOCTYPE html>
<html>
  <head>
    <meta http-equiv="Content-Type" content="text/html;charset=utf-8">
    <title>CartoDB + D3 Bubble Map</title>
    <script src="https://d3js.org/d3.v3.min.js"></script>
    <script src="https://libs.cartocdn.com/cartodb.js/v2/cartodb.js"></script>
    <style type="text/css">

body{
        background:white;
    }
    svg {
      width: 960px;
      height: 500px;
      background: #4a8dcb;
    }
    svg:active {
      cursor: move;
      cursor: -moz-grabbing;
      cursor: -webkit-grabbing;
    }
    .globe {
      fill: #4a8dcb;
    }
    #first_layer path {
      fill-opacity:0.8;
      fill: #222;
      stroke: #ddd;
      stroke-width:0.5px;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    #second_layer circle {
      cursor: pointer;
      fill-opacity:1;
      fill: white;
      stroke-width:0.1px;
      stroke:black;
      stroke-linecap: round;
      stroke-linejoin: round;
    }
    .halo {
      font-weight: 700;
      fill: none;
      stroke: white;
      stroke-width:4px;
      font-size: 14px; 
    }
    .text {
      font-weight: 700;
      fill: #777;
      stroke: none;
      stroke-width:0px;
      font-size: 14px; 
    }

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

var first_layer = 'd3_world_borders';
    var second_layer = 'd3_populated_places';

var sql = new cartodb.SQL({ user: 'viz2', format: 'geojson', dp: 5});

// Define our SVG element outside our SQL functions
    var svg = d3.select("body")
            .append("svg")
            .call(d3.behavior.zoom()
                .on("zoom", redraw))
            .append("g");

// Our projection.
    var xy = d3.geo.mercator().scale(5);
        xy.scale(2500);
        xy.center([40,30]);

svg.append("g").attr("id", "first_layer");
    svg.append("g").attr("id", "second_layer");

var path = d3.geo.path();

sql.execute("SELECT ST_Simplify(the_geom,0.01) as the_geom FROM {{table_name}} WHERE the_geom IS NOT NULL", {table_name: first_layer})
      .done(function(collection) {
          svg.select("#first_layer")
            .selectAll("path")
              .data(collection.features)
            .enter().append("path")
            .attr("d", path.projection(xy));
      })
      .error(function(errors) {
        // console.log('Errors! Oh no!')
      });

sql.execute("SELECT the_geom, 4/sqrt(scalerank) as pop, adm1name as name FROM {{table_name}} WHERE the_geom IS NOT NULL AND pop_max > 10^5", {table_name: second_layer})
        .done(function(collection) {

var label = svg.append("sgv:g")

svg.select("#second_layer")
            .selectAll("path")
            .data(collection.features)
            .enter()
            .append("circle")
            .attr("r", function(d){ return d.properties.pop })
          .attr("cy", function(){ return xy([0,Math.random()*180.0-90])[1]})
          .attr("cx", function(){ return xy([Math.random()*360.0-180,0])[0]})
          .attr("d", path.projection(xy))
            .on("mousedown", function(t){
                d3.selectAll("text").remove(); 
              label.append("svg:text")
                .attr("x", xy(t.geometry.coordinates)[0])
                .attr("y", xy(t.geometry.coordinates)[1])
                .attr("class", "halo")
                .text(t.properties.name);
              label.append("svg:text")
                .attr("x", xy(t.geometry.coordinates)[0])
                .attr("y", xy(t.geometry.coordinates)[1])
                .attr("class", "text")
                .text(t.properties.name);
              })
            .on("mouseout", function(){
              })
          .transition()
          .attr("cy", function(d){ return xy(d.geometry.coordinates)[1] })
          .attr("cx", function(d){ return xy(d.geometry.coordinates)[0] })
          .duration(function(d){ return 800*d.properties.pop })
          .delay(100) 
        })
        .error(function(errors) {
          // console.log('Errors! Oh no!')
        });

function redraw() {
      svg.attr("transform", "translate(" + d3.event.translate + ")scale(" + d3.event.scale + ")");
    }

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

Modified http://d3js.org/d3.v3.min.js to a secure url

Modified http://libs.cartocdn.com/cartodb.js/v2/cartodb.js to a secure url

https://d3js.org/d3.v3.min.js

https://libs.cartocdn.com/cartodb.js/v2/cartodb.js