D3 Examples - Mapping LA

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<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <meta name='viewport' content='initial-scale=1,maximum-scale=1,user-scalable=no' />
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script src='https://api.mapbox.com/mapbox-gl-js/v0.31.0/mapbox-gl.js'></script>
  <link href='https://api.mapbox.com/mapbox-gl-js/v0.31.0/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%;
    }
    canvas {
      position: absolute;
      width: 100%;
      height: 100%;
    }
  </style>
</head>
​
<body>
  <div id="map"></div>
  <script>
    function buildUrl(url, queryParams) {
      url += '?';
      queryParams.forEach(function(param){
        url += `${param}&`
      })
      return url.slice(0, -1);
    }
  </script>
​
  <script>
    //Setup mapbox-gl map
    mapboxgl.accessToken = 'pk.eyJ1Ijoiam9uc2Fka2EiLCJhIjoiY2l4ejkzM3FuMDA0bzMycDl2ZXE0cGw2byJ9.YVf_mtIw3xABynhjwojKQg';
    const map = new mapboxgl.Map({
      container: 'map', // id of the container
      style: 'mapbox://styles/jonsadka/cixzpqzbj003g2srjakw769o5',
      center: [-118.5, 34],
      zoom: 7.5,
      scrollZoom: true
    })
    // map.addControl(new mapboxgl.NavigationControl())
​
    function project(d) {
      const position = getLatLong(d);
      if (position) {
        return map.project(position);
      }
    }
    function getLatLong(d) {
      const longitude = +d.center_lon || (+d.location_1 || {}).longitude;
      const latitude = +d.center_lat || (+d.location_1 || {}).latitude;
      if (longitude && latitude) {
        return new mapboxgl.LngLat(longitude, latitude);
      }
    }
​
    const container = map.getCanvasContainer();
    const canvas = d3.select(container).append('canvas').node();
    const boundingBox = document.body.getBoundingClientRect();
    canvas.width = boundingBox.width;
    canvas.height = boundingBox.height;
    const context = canvas.getContext('2d');
      
    const url06To16 = 'https://data.lacounty.gov/resource/hvzm-fn38.json';
​
    d3.queue()
        // .defer(d3.json, 'https://data.lacounty.gov/resource/mdji-9cym.json')
        .defer(d3.json, buildUrl(url06To16, [
          '$where=units > 22', '$limit=20000', 'yearbuilt=1989'
        ]))
      .await(initialRender)
​
    function initialRender(error, propertyData) {
      if (error) return console.warn(error);
​
      console.log(
        propertyData.length,
        propertyData[0], 
        getLatLong(propertyData[0]), 
        project(propertyData[0])
      )
      
      // Initial render
      render(propertyData);
​
      // re-render our visualization whenever the view changes
      map.on('viewreset', function() {
        context.clearRect(0, 0, boundingBox.width, boundingBox.height);
        render(propertyData);
      })
      map.on('move', function() {
        context.clearRect(0, 0, boundingBox.width, boundingBox.height);
        render(propertyData);
      })
    }
​
    function render(data) {
      const propertyValues = data.reduce(function(_propertyValues, property){
        if (property.roll_totlandimp) {
          _propertyValues.push(+property.roll_totlandimp);
        }
        return _propertyValues;
      }, []);
​
      const propertyValueColor = d3.scaleLog()
        .range(['hsl(62,100%,90%)', 'hsl(228,30%,20%)'])
        .domain([d3.quantile(propertyValues, .01), d3.quantile(propertyValues, .99)])
        .interpolate(d3.interpolateHcl);
​
      context.clearRect(0, 0, boundingBox.width, boundingBox.height);
​
      data.forEach(function(property, idx) {
        const point = project(property);
        if (point) {
          context.fillStyle = propertyValueColor(+property.roll_totlandimp);
          context.beginPath();
          context.arc(point.x, point.y, 4, 0, Math.PI * 2);
          context.fill();
          // context.stroke();
        }
      })
    }
  </script>
</body>
    