JSFiddle - React, Tailwind, and code Playground

by Andrew Good

HTML

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  <script src="//d3js.org/topojson.v1.min.js"></script>
  <script src="d3.geo.tile.min.js"></script>
  
  <script src='https://api.tiles.mapbox.com/mapbox-gl-js/v0.12.0/mapbox-gl.js'></script>
  <link href='https://api.tiles.mapbox.com/mapbox-gl-js/v0.12.0/mapbox-gl.css' rel='stylesheet' />

  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    #map { 
      position:absolute; 
      width: 100%;
      height: 100%;
    }
    svg {
      position: absolute;
      width: 100%;
      height: 100%;
      pointer-events: none;
    }

    circle.mapbox {
      stroke: #111;
      fill-opacity: 0.1;
    }

    circle.d3 {
      fill-opacity: 0.1;
      stroke-width: 3;
      stroke: orange;
    }
  </style>
</head>

<body>
  <div id="map"></div>
  <svg id="overlay2"></svg>
  
 </body>

JavaScript

mapboxgl.accessToken = 'pk.eyJ1IjoiZW5qYWxvdCIsImEiOiJjaWhtdmxhNTIwb25zdHBsejk0NGdhODJhIn0.2-F2hS_oTZenAWc0BMf_uw'
    
    //Setup mapbox-gl map
    var map = new mapboxgl.Map({
      container: 'map', // container id
      style: "mapbox://styles/mapbox/light-v9",
      center: [-96, 38.3],
      zoom: 3,
      
    })
    //map.scrollZoom.disable()
    map.addControl(new mapboxgl.Navigation());

    // Setup our svg layer that we can manipulate with d3
    var container = map.getCanvasContainer()
    var svg = d3.select(container).append("svg")

    // we can project a lonlat coordinate pair using mapbox's built in projection function
    function mapboxProjection(lonlat) {
      var p = map.project(new mapboxgl.LngLat(lonlat[0], lonlat[1]))
      return [p.x, p.y];
    }

    
    // we calculate the scale given mapbox state (derived from viewport-mercator-project's code)
    // to define a d3 projection
    function getD3() {
      var bbox = document.body.getBoundingClientRect();
      var center = map.getCenter();
      var zoom = map.getZoom();
      // 512 is hardcoded tile size, might need to be 256 or changed to suit your map config
      var scale = (512) * 0.5 / Math.PI * Math.pow(2, zoom);

      var d3projection = d3.geo.mercator()
        .center([center.lng, center.lat])
        .translate([bbox.width/2, bbox.height/2])
        .scale(scale);

      return d3projection;
    }
    // calculate the original d3 projection
    var d3Projection = getD3();
    
    var tile = d3.geo.tile()
    .scale(d3Projection.scale() * 2 * Math.PI)
    .translate(d3Projection([0, 0]))
    .zoomDelta((window.devicePixelRatio || 1) - .5);
    
    
    // we want to render the same point
    var point = [-96, 38.3]
  
    var mapboxCircle = svg.append("circle").classed("mapbox", true)
    var d3Circle = svg.append("circle").classed("d3", true)

    var path = d3.geo.path()
      .projection(d3Projection)
    
    var clipped = svg.append("g")
      .attr("clip-path",...