Orthographic Zoom I by curran

A first attempt at panning and zooming with Orthographic projection. See also Orthographic Zoom II.

Uses world-110m geographic shapes from TOPOJSON World Atlas.

Inspired by

index.html

<!DOCTYPE html>
<head>
  <meta charset="utf-8">
  <script src="https://d3js.org/d3.v4.min.js"></script>
  <script src="https://d3js.org/topojson.v1.min.js"></script>
</head>
<body>
  <svg width="960" height="500"></svg>
  <script>
    const svg = d3.select('svg');
    const path = svg.append('path');
    const projection = d3.geoOrthographic();
    const initialScale = projection.scale();
    const geoPath = d3.geoPath().projection(projection);
    const sensitivity = 58;
    
    d3.json('world-110m.json', (error, world) => {
      const land = topojson.feature(world, world.objects.land);
      const render = () => path.attr('d', geoPath(land));
      render();
      svg
        .call(d3.drag().on('drag', () => {
          const rotate = projection.rotate();
          const k = sensitivity / projection.scale();
          projection.rotate([
            rotate[0] + d3.event.dx * k,
            rotate[1] - d3.event.dy * k
          ])
          render();
        }))
        .call(d3.zoom().on('zoom', () => {
          projection.scale(initialScale * d3.event.transform.k);
          render();
        }));
    });
  </script>
</body>