var HeatmapOverlay = require('react-map-gl-heatmap-overlay');
var cities = require('example-cities');

    render() {
      return <MapGL {...viewport}>
        <HeatmapOverlay locations={cities} {...viewport}/>
      </MapGL>;
    }

    render() {
      return <MapGL ...viewport>
        <HeatmapOverlay locations={houses} {...viewport}
          lngLatAccessor={(house) => [house.get('lng'), house.get('lat')]} />
      </MapGL>;
    }

    intensityAccessor: (location) => {1 / 10}
    sizeAccessor: (location) => 40,
    // If not specified, defaults to Viridis.
    gradientColors: Immutable.List(['blue', 'red'])