Basemaps, projections and offsets

• Return a BitmapLayer from renderSubLayers using props.tile.boundingBox as bounds.
• Use MapboxOverlay with interleaved: false unless depth testing against 3D buildings is needed.
• On Leaflet, sync viewState on move and use map.getZoom() minus one.

var basemap = new deck.TileLayer({
  id: 'basemap',
  data: 'https://services.arcgisonline.com/ArcGIS/rest/services/Canvas/World_Dark_Gray_Base/MapServer/tile/{z}/{y}/{x}',
  minZoom: 0,
  maxZoom: 16,
  tileSize: 256,
  renderSubLayers: function (props) {
    var bb = props.tile.boundingBox;   // [[西, 南], [东, 北]]
    return new deck.BitmapLayer(props, {
      data: null,
      image: props.data,
      bounds: [bb[0][0], bb[0][1], bb[1][0], bb[1][1]]
    });
  }
});

var deckgl = new deck.Deck({
  canvas: 'cv',
  width: '100%',
  height: '100%',
  initialViewState: { longitude: 116.39, latitude: 39.9, zoom: 9, pitch: 0 },
  controller: true,
  layers: [basemap, dataLayer]      // 先底图，后数据
});

var overlay = new deck.MapboxOverlay({
  interleaved: false,               // 需要与三维建筑混合时设为 true
  layers: [dataLayer]
});

map.addControl(overlay);

• TMS services need the y axis flipped, or tiles render upside down or return 404.
• Baidu BD-09 and Gaode GCJ-02 tiles shift WGS84 data by tens to hundreds of meters.