WWSD #2-a: Leaflet Choropleth

Working with spatial data

Example #1

Getting started with Leaflet

Built with blockbuilder.org

forked from enjalot's block: WWSD #1: Leaflet starter

forked from enjalot's block: WWSD #1-a: Leaflet Rivers

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://cdnjs.cloudflare.com/ajax/libs/d3/3.5.5/d3.min.js"></script>
  <link rel="stylesheet" href="https://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.css" />
   <script src="https://cdnjs.cloudflare.com/ajax/libs/leaflet/0.7.7/leaflet.min.js"></script>
  
  <style>
    body { margin:0;position:fixed;top:0;right:0;bottom:0;left:0; }
    #map {
      height: 100%;
    }
  </style>
</head>

<body>
  <div id="map"></div>
  <script>
    var map = L.map('map').setView([30, 0], 2);

L.tileLayer('https://{s}.tile.osm.org/{z}/{x}/{y}.png', {
        attribution: '&copy; <a href="https://osm.org/copyright">OpenStreetMap</a> contributors'
    }).addTo(map);
    
    var url = "https://enjalot.github.io/wwsd/data/world/ne_50m_admin_0_countries.geojson"
    d3.json(url, function(err, data) {
      
      var maxPop = d3.max(data.features, function(d) { return d.properties.pop_est })
      
      var color = d3.scale.threshold()
      .domain([0, 1000000, 100000000, 1000000000])
      .range(["#ffffcc","#c2e699","#78c679","#31a354","#006837"])
      
      L.geoJson(data, { 
        style: function(feature) {
          return { 
            fillColor: color(feature.properties.pop_est), 
            fillOpacity:0.4, 
            weight: 1,
      		}
        }
      }).addTo(map)
    })
  </script>
</body>

Modified http://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js to a secure url

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

https://cdn.leafletjs.com/leaflet/v0.7.7/leaflet.js