mapbox · ibesora · Jun 27, 2017 · Jun 28, 2017 · Jan 19, 2018 · Jan 19, 2018
diff --git a/debug/hillshade.html b/debug/hillshade.html
@@ -12,6 +12,52 @@
 </head>
 
 <body>
+
+<style>
+    #menu {
+        background: #fff;
+        position: absolute;
+        z-index: 1;
+        top: 10px;
+        right: 10px;
+        border-radius: 3px;
+        width: 120px;
+        border: 1px solid rgba(0,0,0,0.4);
+        font-family: 'Open Sans', sans-serif;
+    }
+
+    #menu a {
+        font-size: 13px;
+        color: #404040;
+        display: block;
+        margin: 0;
+        padding: 0;
+        padding: 10px;
+        text-decoration: none;
+        border-bottom: 1px solid rgba(0,0,0,0.25);
+        text-align: center;
+    }
+
+    #menu a:last-child {
+        border: none;
+    }
+
+    #menu a:hover {
+        background-color: #f8f8f8;
+        color: #404040;
+    }
+
+    #menu a.active {
+        background-color: #3887be;
+        color: #ffffff;
+    }
+
+    #menu a.active:hover {
+        background: #3074a4;
+    }
+</style>
+
+<nav id="menu"></nav>
 <div id='map'></div>
 
 <script src='/dist/mapbox-gl-dev.js'></script>
@@ -26,19 +72,69 @@
 });
 
 map.on('load', function () {
-    map.addSource('dem', {
+
+    map.addSource('mapbox-dem', {
         "type": "raster-dem",
-        "url": "mapbox://mapbox.terrain-rgb"
+        "url": "mapbox://mapbox.terrain-rgb",
+        "tileSize": 256
     });
     map.addLayer({
-        "id": "hillshading",
-        "source": "dem",
+        "id": "Mapbox data",
+        "source": "mapbox-dem",
         "type": "hillshade"
     // insert below waterway-river-canal-shadow;
     // where hillshading sits in the Mapbox Outdoors style
     }, 'waterway-river-canal-shadow');
+
+    map.addSource('terrarium-dem', {
+        "type": "raster-dem",
+        "encoding": "terrarium",
+        "tiles": [
+            "https://s3.amazonaws.com/elevation-tiles-prod/terrarium/{z}/{x}/{y}.png"
+        ],
+        "tileSize": 256
+    });
+    map.addLayer({
+        "id": "Terrarium data",
+        "source": "terrarium-dem",
+        "type": "hillshade",
+        "layout": {
+            "visibility": "none"
+        }
+    // insert below waterway-river-canal-shadow;
+    // where hillshading sits in the Mapbox Outdoors style
+    }, 'waterway-river-canal-shadow');
+
 });
 
+var toggleableLayerIds = ['Mapbox data', 'Terrarium data'];
+
+for (var i = 0; i < toggleableLayerIds.length; i++) {
+    var id = toggleableLayerIds[i];
+
+    var link = document.createElement('a');
+    link.href = '#';
+    link.className = (i === 0) ? 'active' : '';
+    link.textContent = id;
+
+    link.onclick = function (e) {
+        var clickedLayer = this.textContent;
+        e.preventDefault();
+        e.stopPropagation();
+
+        if (this.className === '') {
+            var activeLayer = document.getElementsByClassName('active')[0];
+            activeLayer.className = '';
+            map.setLayoutProperty(activeLayer.textContent, 'visibility', 'none');
+            this.className = 'active';
+            map.setLayoutProperty(clickedLayer, 'visibility', 'visible');
+        }
+    };
+
+    var layers = document.getElementById('menu');
+    layers.appendChild(link);
+}
+
 </script>
 </body>
 </html>
diff --git a/flow-typed/style-spec.js b/flow-typed/style-spec.js
@@ -102,7 +102,8 @@ declare type RasterDEMSourceSpecification = {
     "minzoom"?: number,
     "maxzoom"?: number,
     "tileSize"?: number,
-    "attribution"?: string
+    "attribution"?: string,
+    "encoding"?: "terrarium" | "mapbox"
 }
 
 declare type GeojsonSourceSpecification = {|

diff --git a/src/data/dem_data.js b/src/data/dem_data.js
@@ -57,22 +57,14 @@ class DEMData {
         this.loaded = !!data;
     }
 
-    loadFromImage(data: RGBAImage) {
+    loadFromImage(data: RGBAImage, encoding?: "mapbox" | "terrarium") {
         if (data.height !== data.width) throw new RangeError('DEM tiles must be square');
 
         // Build level 0
         const level = this.level = new Level(data.width, data.width / 2);
         const pixels = data.data;
 
-        // unpack
-        for (let y = 0; y < level.dim; y++) {
-            for (let x = 0; x < level.dim; x++) {
-                const i = y * level.dim + x;
-                const j = i * 4;
-                // decoding per https://blog.mapbox.com/global-elevation-data-6689f1d0ba65
-                level.set(x, y, this.scale * ((pixels[j] * 256 * 256 + pixels[j + 1] * 256.0 + pixels[j + 2]) / 10.0 - 10000.0));
-            }
-        }
+        this.unpackData(level, pixels, encoding || "mapbox");
 
         // in order to avoid flashing seams between tiles, here we are initially populating a 1px border of pixels around the image
         // with the data of the nearest pixel from the image. this data is eventually replaced when the tile's neighboring
@@ -95,6 +87,26 @@ class DEMData {
         this.loaded = true;
     }
 
+    _unpackMapbox(r: number, g: number, b: number) {
+        return ((r * 256 * 256 + g * 256.0 + b) / 10.0 - 10000.0);
+    }
+
+    _unpackTerrarium(r: number, g: number, b: number) {
+        return ((r * 256 + g + b / 256) - 32768.0);
+    }
+
+    unpackData(level: Level, pixels: Uint8Array | Uint8ClampedArray, encoding: string) {
+        const unpackFunctions = {"mapbox": this._unpackMapbox, "terrarium": this._unpackTerrarium};
+        const unpack = unpackFunctions[encoding];
+        for (let y = 0; y < level.dim; y++) {
+            for (let x = 0; x < level.dim; x++) {
+                const i = y * level.dim + x;
+                const j = i * 4;
+                level.set(x, y, this.scale * unpack(pixels[j], pixels[j + 1], pixels[j + 2]));
+            }
+        }
+    }
+
     getPixels() {
         return new RGBAImage({width: this.level.dim + 2 * this.level.border, height: this.level.dim + 2 * this.level.border}, new Uint8Array(this.level.data.buffer));
     }

diff --git a/src/source/raster_dem_tile_source.js b/src/source/raster_dem_tile_source.js
@@ -15,11 +15,14 @@ import type {Callback} from '../types/callback';
 
 
 class RasterDEMTileSource extends RasterTileSource implements Source {
+    encoding: "mapbox" | "terrarium";
+
     constructor(id: string, options: RasterDEMSourceSpecification, dispatcher: Dispatcher, eventedParent: Evented) {
         super(id, options, dispatcher, eventedParent);
         this.type = 'raster-dem';
         this.maxzoom = 22;
         this._options = util.extend({}, options);
+        this.encoding = options.encoding || "mapbox";
     }
 
     serialize() {
@@ -29,6 +32,7 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
             tileSize: this.tileSize,
             tiles: this.tiles,
             bounds: this.bounds,
+            encoding: this.encoding
         };
     }
 
@@ -55,7 +59,8 @@ class RasterDEMTileSource extends RasterTileSource implements Source {
                     uid: tile.uid,
                     coord: tile.tileID,
                     source: this.id,
-                    rawImageData: rawImageData
+                    rawImageData: rawImageData,
+                    encoding: this.encoding
                 };
 
                 if (!tile.workerID || tile.state === 'expired') {

diff --git a/src/source/raster_dem_tile_worker_source.js b/src/source/raster_dem_tile_worker_source.js
@@ -22,14 +22,15 @@ class RasterDEMTileWorkerSource {
 
     loadTile(params: WorkerDEMTileParameters, callback: WorkerDEMTileCallback) {
         const source = params.source,
-            uid = params.uid;
+            uid = params.uid,
+            encoding = params.encoding || "mapbox";
 
         if (!this.loading[source])
             this.loading[source] = {};
 
         const dem = new DEMData(uid);
         this.loading[source][uid] = dem;
-        dem.loadFromImage(params.rawImageData);
+        dem.loadFromImage(params.rawImageData, encoding);
         delete this.loading[source][uid];
 
         this.loaded[source] = this.loaded[source] || {};

diff --git a/src/source/worker_source.js b/src/source/worker_source.js
@@ -28,7 +28,8 @@ export type WorkerTileParameters = TileParameters & {
 
 export type WorkerDEMTileParameters = TileParameters & {
     coord: { z: number, x: number, y: number, w: number },
-    rawImageData: RGBAImage
+    rawImageData: RGBAImage,
+    encoding: "mapbox" | "terrarium"
 };
 
 export type WorkerTileResult = {

diff --git a/src/style-spec/reference/v8.json b/src/style-spec/reference/v8.json
@@ -231,7 +231,7 @@
       "type": "enum",
       "values": {
         "raster-dem": {
-            "doc": "A raster DEM source using Mapbox Terrain RGB"
+            "doc": "A RGB-encoded raster DEM source"
         }
       },
       "doc": "The type of the source."
@@ -272,6 +272,19 @@
       "type": "string",
       "doc": "Contains an attribution to be displayed when the map is shown to a user."
     },
+    "encoding": {
+      "type": "enum",
+      "values": {
+        "terrarium": {
+          "doc": "Terrarium format PNG tiles. See https://aws.amazon.com/es/public-datasets/terrain/ for more info."
+        },
+        "mapbox": {
+          "doc": "Mapbox Terrain RGB tiles. See https://www.mapbox.com/help/access-elevation-data/#mapbox-terrain-rgb for more info."
+        }
+      },
+      "default": "mapbox",
+      "doc": "The encoding used by this source. Mapbox Terrain RGB is used by default"
+    },
     "*": {
       "type": "*",
       "doc": "Other keys to configure the data source."
@@ -502,7 +515,7 @@
           }
         },
         "hillshade": {
-          "doc": "Client-side hillshading visualization based on DEM data. Currently, the implementation only supports Mapbox Terrain RGB tiles",
+          "doc": "Client-side hillshading visualization based on DEM data. Currently, the implementation only supports Mapbox Terrain RGB and Mapzen Terrarium tiles.",
           "sdk-support": {
             "basic functionality": {
               "js": "0.43.0"