D3 Examples - Hotspots

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<!DOCTYPE html>
<meta charset="utf-8">
<body>
<script src="https://d3js.org/d3.v4.min.js"></script>
<script src="https://d3js.org/topojson.v2.min.js"></script>
<script>
​
var width = 960,
    height = 600;
​
var radius = height / 2 - 5,
    scale = radius,
    velocity = .02;
​
var projection = d3.geoOrthographic()
    .translate([width / 2, height / 2])
    .scale(scale)
    .clipAngle(90);
​
var canvas = d3.select("body").append("canvas")
    .attr("width", width)
    .attr("height", height);
​
var context = canvas.node().getContext("2d");
​
var path = d3.geoPath()
    .projection(projection)
    .context(context);
​
var zoom = d3
    .zoom()
    .on("zoom start end", zoomed)
    .scaleExtent([0.7, 5])
    .translateExtent([[0,0], [width, height]]);
​
canvas.call(zoom);
​
var init_scale = projection.scale(),
  init_translate = projection.translate();
​
function zoomed() {
  var t = d3.event.transform;
  projection.scale(init_scale * t.k)
    .translate(t.apply(init_translate));
}
​
d3.json("https://gist.githubusercontent.com/mbostock/4090846/raw/d534aba169207548a8a3d670c9c2cc719ff05c47/world-110m.json", function(error, world) {
  if (error) throw error;
​
  var land = topojson.feature(world, world.objects.land);
  
  var places = {
    "type": "FeatureCollection",
    "bbox": [-126.507568, 3.590178, 98.217773, 51.481383],
    "features": [{
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [98.217773, 3.590178]
      },
      "properties": {
        "name": "Leuser Ecosystem"
      }
    }, {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [-76.025391, 50.303376]
      },
      "properties": {
        "name": "Broadback Forest"
      }
    }, {
      "type": "Feature",
      "geometry": {
        "type": "Point",
        "coordinates": [-126.507568, 51.481383]
      },
      "properties": {
        "name": "Great Bear Rainforest"
      }
    }]
  };
  
  d3.timer(function(elapsed) {
    context.clearRect(0, 0, width, height);
​
    projection.rotate([velocity * elapsed, -40]);
    context.beginPath();
    path(land);
    context.fillStyle = '#333';
    context.fill();
    
    context.beginPath();
    path(places);
    path.pointRadius(10);
    context.strokeStyle = 'magenta';
    context.stroke();
    context.fillStyle = 'magenta';
    context.fill();
​
    context.strokeStyle = 'black';
    context.beginPath();
    path({type:"Sphere"});
    context.lineWidth = 2.5;
    context.stroke();
  });
});
​
d3.select(self.frameElement).style("height", height + "px");
​
</script>
</body>
​
    