Dot on a map playground

<!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='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' />

<body>
  <div id="map"></div>
  <script>
  
    mapboxgl.accessToken = 'pk.eyJ1IjoiZm94YnkiLCJhIjoiY2o2NHN5eTdwMXAycTJ5bDR1bnE0NzQ0OSJ9.8EiSAtpBcpC3DywBjWpIkw'
    
    //Setup mapbox-gl map
    var map = new mapboxgl.Map({
      container: 'map', // container id
       style: 'mapbox://styles/mapbox/streets-v9',
      center: [12.5797,55.6663],
      zoom: 13.5,
      
    })
    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")

// re-render our visualization whenever the view changes
      map.on("viewreset", function() {
        render()
      })
      map.on("move", function() {
        render()
      })

// render our initial visualization
      render()
    })

</script>
</body>

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

https://api.tiles.mapbox.com/mapbox-gl-js/v0.12.0/mapbox-gl.js