dots on a map

From enjalots youtube tutorial :

https://www.youtube.com/watch?v=OnqDeuRW5CI&feature=youtu.be

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src='https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.js'></script>
  <link href='https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.css' rel='stylesheet' />
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    #map {
      position: absolute;
      width: 100%;
      height: 100%
        
    }
  </style>
</head>

<body>
  <div id="map"></div>
  <script>
    
    L.mapbox.accessToken = 'pk.eyJ1IjoiZW5qYWxvdCIsImEiOiJjaWhtdmxhNTIwb25zdHBsejk0NGdhODJhIn0.2-F2hS_oTZenAWc0BMf_uw'
    
    //Setup our Leaflet map using Mapbox.js
    // ID, style, zoom options, location centre, initial zoom
    var map = L.mapbox.map('map', 'mapbox.pencil', {maxZoom: 18, minZoom: 14})
    .setView([51.5119112,-0.10000], 15);
    
    function project(latlng) {
      var array = [+latlng.lat, +latlng.lon]
    	var point = map.latLngToLayerPoint(L.latLng(latlng));
      // console.log("point", point)
      return point;
    }
    
    // Setup our svg layer that we can manipulate with d3
    var svg = d3.select(map.getPanes().overlayPane)
      .append("svg");
    // group inside data where we add the d3 elements
    var g = svg.append("g").attr("class", "leaflet-zoom-hide");
    
  	d3.csv("dots.csv", function(err, data) {
      // console.log("data", data);
      // console.log(project(data[0]));
      var dots = g.selectAll("circle").data(data)
      
      dots.enter()
        .append("circle")
      
      function update() {
        // We need to reposition our SVG and our containing group when the map
        // repositions via zoom or pan
        // https://github.com/zetter/voronoi-maps/blob/master/lib/voronoi_map.js
        var bounds = map.getBounds();
        var topLeft = map.latLngToLayerPoint(bounds.getNorthWest())
        var bottomRight = map.latLngToLayerPoint(bounds.getSouthEast())
        console.log(bounds, topLeft, bottomRight);
        svg.style("width", map.getSize().x + "px")
          .style("height", map.getSize().y + "px")
          .style("left", topLeft.x + "px")
          .style("top", topLeft.y + "px");
        g.attr("transform", "translate(" + -topLeft.x + "," + -topLeft.y + ")");
      
      dots.attr({
        cx: function(d) { return project(d).x },
				cy: function(d) { return project(d).y },
        r: 5
      })
      }
      update()
      map.on("viewreset", update);
     	map.on("move", update);
    })
    
  </script>
</body>

https://api.mapbox.com/mapbox.js/v2.2.3/mapbox.js

https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js