CARTO for deck.gl

CARTO for deck.gl

Zoom Based Styling

This example shows how to apply zoom-based styling to a proportional symbol map. Based on this blogpost.

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<html>
  <head>
    <!-- FONT -->
    <link
      href="https://fonts.googleapis.com/css2?family=Open+Sans:wght@400;600&display=swap"
      rel="stylesheet"
    />

    <script src="https://unpkg.com/deck.gl@^8.6.0/dist.min.js"></script>
    <script src="https://unpkg.com/@deck.gl/carto@^8.6.0/dist.min.js"></script>
    
    <script src="https://libs.cartocdn.com/mapbox-gl/v1.13.0/mapbox-gl.js"></script>
    <link href="https://libs.cartocdn.com/mapbox-gl/v1.13.0/mapbox-gl.css" rel="stylesheet" />
  </head>

  <body style="margin: 0; padding: 0; font-family: 'Open Sans', Helvetica, sans-serif;">
    <div id="map" style="width: 100vw; height: 100vh;"></div>
  </body>

  <script type="text/javascript">
    deck.carto.setDefaultCredentials({
      username: 'public',
      apiKey: 'default_public',
    });

    let zoom = 1.5;
    let deckgl;

    const renderLayer = () => {
      const layer = new deck.carto.CartoLayer({
        id: 'world_population',
        type: deck.carto.MAP_TYPES.QUERY,
        data: `SELECT the_geom_webmercator, country_name, continent_name, pop_2015 
                  FROM world_population_2015 
                ORDER BY pop_2015 DESC`,
        opacity: 0.7,
        getFillColor: deck.carto.colorCategories({
          attr: 'continent_name',
          domain: [
            'Africa',
            'Asia',
            'Europe',
            'North America',
            'Oceania',
            'South America'
          ],
          colors: [
            [117, 68, 92],
            [175, 100, 88],
            [213, 167, 91],
            [115, 111, 76],
            [91, 120, 142],
            [76, 78, 143]
          ]
        }),
        getLineColor: [255, 255, 255, 204],
        pointRadiusUnits: 'pixels',
        getPointRadius: (d) => {
          // Proportional symbol map + zoom based styling
          // Maximum symbol size: 30 px * zoom level
          // Maximum population square root (China): 27620.2642999664
          return 30.0 * zoom * Math.sqrt(d.properties.pop_2015) / 27620.2642999664;
        },
        lineWidthMinPixels: 1,
        updateTriggers: {
          getPointRadius: [zoom]
        },
        pickable: true,
      });

      deckgl.setProps({
        layers: [layer]
      });
    };

    deckgl = new deck.DeckGL({
      container: 'map',
      mapStyle: deck.carto.BASEMAP.VOYAGER,

      initialViewState: {
        latitude: 15,
        longitude: 10,
        zoom: zoom,
      },
      controller: true,

      onViewStateChange: ({viewState}) => {
        zoom = viewState.zoom;
        renderLayer();
      },

      getTooltip: ({ object }) => {
        if (!object) return false;
        return {
          html: `${object.properties.country_name}: ${object.properties.pop_2015}`,
        };
      },
    });

  </script>
</html>