const Earth = Kapsule({

  methods: {
    redraw: function(state) {
      state.terrainRender && state.terrainRender();
      return this;
    }
  },

  init(svg, state, projection) {
    const path = d3.geoPath()
      .projection(projection);

    state.terrainRender = () => svg.selectAll('path.geo').attr('d', path);

    fetch('//unpkg.com/world-atlas@1/world/110m.json')
      .then(r => r.json())
      .then(world => {
        // water
        svg.append('path').attr('class', 'geo sphere')
          .datum({ type: 'Sphere' });

        // land
        svg.append('path').attr('class', 'geo land')
          .datum(topojson.feature(world, world.objects.land).features[0]);

        // graticules
        svg.append('path').attr('class', 'geo graticule')
          .datum(d3.geoGraticule10());

        state.terrainRender();
      });
  }
});