Improve and simplify Mercator layers management

src/layer/BMNGLandsatLayer.js

@@ -49,12 +49,9 @@ define([
          */
         var BMNGLandsatLayer = function () {
             // This LevelSet configuration captures the Landsat resolution of 1.38889E-04 degrees/pixel
-            TiledImageLayer.call(this,
+            TiledImageLayer.call(this, "Blue Marble & Landsat",
                 Sector.FULL_SPHERE, new Location(45, 45), 12, "image/jpeg", "BMNGLandsat256", 256, 256);
 
-            this.displayName = "Blue Marble & Landsat";
-            this.pickEnabled = false;
-
             this.urlBuilder = new WmsUrlBuilder("https://worldwind25.arc.nasa.gov/wms",
                 "BlueMarble-200405,esat", "", "1.3.0");
         };

src/layer/BMNGLayer.js

@@ -52,12 +52,9 @@ define([
          */
         var BMNGLayer = function (layerName) {
             // This LevelSet configuration captures the Blue Marble resolution of 4.166666667E-03 degrees/pixel
-            TiledImageLayer.call(this,
+            TiledImageLayer.call(this, "Blue Marble",
                 Sector.FULL_SPHERE, new Location(45, 45), 7, "image/jpeg", layerName || "BMNG256", 256, 256);
 
-            this.displayName = "Blue Marble";
-            this.pickEnabled = false;
-
             this.urlBuilder = new WmsUrlBuilder("https://worldwind25.arc.nasa.gov/wms",
                 layerName || "BlueMarble-200405", "", "1.3.0");
         };

src/layer/BingTiledImageLayer.js

@@ -29,21 +29,15 @@
  * @exports BingTiledImageLayer
  */
 define([
-        '../geom/Angle',
         '../util/Color',
-        '../geom/Location',
-        '../util/Offset',
         '../shapes/ScreenImage',
-        '../geom/Sector',
-        '../layer/MercatorTiledImageLayer'
+        '../layer/MercatorTiledImageLayer',
+        '../WorldWind'
     ],
-    function (Angle,
-              Color,
-              Location,
-              Offset,
+    function (Color,
               ScreenImage,
-              Sector,
-              MercatorTiledImageLayer) {
+              MercatorTiledImageLayer,
+              WorldWind) {
         "use strict";
 
         /**
@@ -58,18 +52,16 @@ define([
          * @param {String} displayName This layer's display name.
          */
         var BingTiledImageLayer = function (displayName) {
-            this.imageSize = 256;
-
-            MercatorTiledImageLayer.call(this,
-                new Sector(-85.05, 85.05, -180, 180), new Location(85.05, 180), 23, "image/jpeg", displayName,
-                this.imageSize, this.imageSize);
-
-            this.displayName = displayName;
+            MercatorTiledImageLayer.call(this, displayName, 23, "image/jpeg", displayName, 256, 1);
 
             // TODO: Picking is enabled as a temporary measure for screen credit hyperlinks to work (see Layer.render)
             this.pickEnabled = true;
 
             this.detectBlankImages = true;
+
+            // Set the detail control so the resolution is a close match 
+            // to the resolution on the Bing maps website
+            this.detailControl = 1.25;
         };
 
         // Internal use only. Intentionally not documented.
@@ -88,16 +80,6 @@ define([
             }
         };
 
-        // Overridden from TiledImageLayer.
-        BingTiledImageLayer.prototype.createTopLevelTiles = function (dc) {
-            this.topLevelTiles = [];
-
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 0, 0));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 0, 1));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 1, 0));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 1, 1));
-        };
-
         BingTiledImageLayer.prototype.renderLogo = function (dc) {
             if (!BingTiledImageLayer.logoImage) {
                 BingTiledImageLayer.logoImage = new ScreenImage(WorldWind.configuration.bingLogoPlacement,
@@ -113,10 +95,5 @@ define([
             }
         };
 
-        // Determines the Bing map size for a specified level number.
-        BingTiledImageLayer.prototype.mapSizeForLevel = function (levelNumber) {
-            return 256 << (levelNumber + 1);
-        };
-
         return BingTiledImageLayer;
     });

src/layer/DigitalGlobeTiledImageLayer.js

@@ -29,20 +29,14 @@
  * @exports DigitalGlobeTiledImageLayer
  */
 define([
-        '../geom/Angle',
         '../error/ArgumentError',
         '../util/Color',
-        '../geom/Location',
         '../util/Logger',
-        '../geom/Sector',
         '../layer/MercatorTiledImageLayer'
     ],
-    function (Angle,
-              ArgumentError,
+    function (ArgumentError,
               Color,
-              Location,
               Logger,
-              Sector,
               MercatorTiledImageLayer) {
         "use strict";
 
@@ -73,12 +67,7 @@ define([
                         "The access token is null or undefined."));
             }
 
-            this.imageSize = 256;
-            displayName = displayName || "Digital Globe";
-
-            MercatorTiledImageLayer.call(this,
-                new Sector(-85.05, 85.05, -180, 180), new Location(85.05, 180), 19, "image/jpeg", displayName,
-                this.imageSize, this.imageSize);
+            MercatorTiledImageLayer.call(this, displayName || "Digital Globe", 19, "image/jpeg", displayName, 256, 1);
 
             /**
              * The map ID identifying the dataset displayed by this layer.
@@ -94,7 +83,6 @@ define([
             this.accessToken = accessToken;
             //"pk.eyJ1IjoiZGlnaXRhbGdsb2JlIiwiYSI6IjljZjQwNmEyMTNhOWUyMWM5NWUzYWIwOGNhYTY2ZDViIn0.Ju3tOUUUc0C_gcCSAVpFIA";
 
-            this.displayName = displayName;
             // TODO: Picking is enabled as a temporary measure for screen credit hyperlinks to work (see Layer.render)
             this.pickEnabled = true;
 
@@ -156,21 +144,6 @@ define([
             }
         };
 
-        // Overridden from TiledImageLayer.
-        DigitalGlobeTiledImageLayer.prototype.createTopLevelTiles = function (dc) {
-            this.topLevelTiles = [];
-
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 0, 0));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 0, 1));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 1, 0));
-            this.topLevelTiles.push(this.createTile(null, this.levels.firstLevel(), 1, 1));
-        };
-
-        // Determines the Bing map size for a specified level number.
-        DigitalGlobeTiledImageLayer.prototype.mapSizeForLevel = function (levelNumber) {
-            return 256 << (levelNumber + 1);
-        };
-
         return DigitalGlobeTiledImageLayer;
     }
 )

src/layer/LandsatRestLayer.js

@@ -63,10 +63,8 @@ define([
         var LandsatRestLayer = function (serverAddress, pathToData, displayName) {
             var cachePath = WWUtil.urlPath(serverAddress + "/" + pathToData);
 
-            TiledImageLayer.call(this, Sector.FULL_SPHERE, new Location(36, 36), 10, "image/png", cachePath, 512, 512);
+            TiledImageLayer.call(this, displayName, Sector.FULL_SPHERE, new Location(36, 36), 10, "image/png", cachePath, 512, 512);
 
-            this.displayName = displayName;
-            this.pickEnabled = false;
             this.urlBuilder = new LevelRowColumnUrlBuilder(serverAddress, pathToData);
         };
 

src/layer/Layer.js

@@ -28,10 +28,7 @@
 /**
  * @exports Layer
  */
-define([
-        '../util/Logger'
-    ],
-    function (Logger) {
+define([], function () {
         "use strict";
 
         /**
@@ -40,6 +37,7 @@ define([
          * @constructor
          * @classdesc Provides an abstract base class for layer implementations. This class is not meant to be instantiated
          * directly.
+         * @param {String} displayName This layer's display name.
          */
         var Layer = function (displayName) {
 
@@ -48,7 +46,7 @@ define([
              * @type {String}
              * @default "Layer"
              */
-            this.displayName = displayName ? displayName : "Layer";
+            this.displayName = displayName || "Layer";
 
             /**
              * Indicates whether to display this layer.

src/layer/MercatorTiledImageLayer.js

@@ -31,12 +31,14 @@
 define([
         '../util/Color',
         '../geom/Sector',
+        '../geom/Location',
         '../layer/TiledImageLayer',
         '../geom/Vec2',
         '../util/WWMath'
     ],
     function (Color,
               Sector,
+              Location,
               TiledImageLayer,
               Vec2,
               WWMath) {
@@ -49,25 +51,43 @@ define([
          * @augments TiledImageLayer
          * @classdesc Provides an abstract layer to support Mercator layers.
          *
-         * @param {Sector} sector The sector this layer covers.
-         * @param {Location} levelZeroDelta The size in latitude and longitude of level zero (lowest resolution) tiles.
+         * @param {String} displayName This layer's display name.
          * @param {Number} numLevels The number of levels to define for the layer. Each level is successively one power
          * of two higher resolution than the next lower-numbered level. (0 is the lowest resolution level, 1 is twice
          * that resolution, etc.)
          * Each level contains four times as many tiles as the next lower-numbered level, each 1/4 the geographic size.
          * @param {String} imageFormat The mime type of the image format for the layer's tiles, e.g., <em>image/png</em>.
          * @param {String} cachePath A string uniquely identifying this layer relative to other layers.
-         * @param {Number} tileWidth The horizontal size of image tiles in pixels.
-         * @param {Number} tileHeight The vertical size of image tiles in pixels.
-         * @throws {ArgumentError} If any of the specified sector, level-zero delta, cache path or image format arguments are
-         * null or undefined, or if the specified number of levels, tile width or tile height is less than 1.
+         * @param {Number} imageSize The horizontal and vertical size of image tiles in pixels.
+         * @param {Number} firstLevelOffset The level offset to skip applying one tile over whole globe and start from e.g. 8x8 tiles.
+         * @throws {ArgumentError} If any of the specified cache path or image format arguments are
+         * null or undefined, or if the specified number of levels or tile size is less than 1.
          */
-        var MercatorTiledImageLayer = function (sector, levelZeroDelta, numLevels, imageFormat, cachePath,
-                                                tileWidth, tileHeight) {
-            TiledImageLayer.call(this,
-                sector, levelZeroDelta, numLevels, imageFormat, cachePath, tileWidth, tileHeight);
+        var MercatorTiledImageLayer = function (displayName, numLevels, imageFormat, cachePath, imageSize, firstLevelOffset) {
+
+            function gudermannian(percent) {
+                var x = percent * Math.PI;
+                // var sinh = (Math.exp(x) - Math.exp(-x)) / 2;
+                var y = Math.exp(x);
+                var sinh = (y - 1 / y) / 2;
+                return Math.atan(sinh) * 180 / Math.PI;
+            }
+
+            function levelZeroDelta(firstLevelOffset) {
+                var levelZeroDelta = 360 / (1 << firstLevelOffset);
+                return new Location(levelZeroDelta / 2, levelZeroDelta);
+            }
+
+            var sector = new Sector(
+                gudermannian(-1), gudermannian(1), -180, 180
+            );
+
+            TiledImageLayer.call(this, displayName,
+                sector, levelZeroDelta(firstLevelOffset), numLevels - firstLevelOffset, imageFormat, cachePath, imageSize, imageSize);
 
             this.detectBlankImages = false;
+            this.imageSize = imageSize;
+            this.firstLevelOffset = firstLevelOffset;
 
             // These pixels are tested in retrieved images to determine whether the image is blank.
             this.testPixels = [
@@ -189,6 +209,36 @@ define([
             return true;
         };
 
+        /**
+         * Calculates map size in pixels for specified level.
+         *
+         * @param {Number} levelNumber The number of level to calculate map size for.
+         */
+        MercatorTiledImageLayer.prototype.mapSizeForLevel = function(levelNumber) {
+            return this.imageSize << (levelNumber + this.firstLevelOffset);
+        };
+
+        // Overridden from TiledImageLayer to add possibility to create simple child layers with URL builder built-in.
+        MercatorTiledImageLayer.prototype.resourceUrlForTile = function(tile, imageFormat) {
+            if (this.urlBuilder) {
+                return this.urlBuilder.urlForTile(tile, imageFormat);
+            } else {
+                return this.getImageSourceUrl(tile.column, tile.row, tile.level.levelNumber + this.firstLevelOffset);
+            }
+        };
+
+        /**
+         * Simple version of URL builder based on commonly used by online maps input parameters x, y and z.
+         *
+         * @param {Number} x The X coordinate of tile.
+         * @param {Number} y The Y coordinate of tile.
+         * @param {Number} z The zoom level of tile.
+         */
+        MercatorTiledImageLayer.prototype.getImageSourceUrl = function(x, y, z) {
+            // Intentionally empty. Can be override in child layer and return URL for specified tile instead of builder
+            return null;
+        };
+
         return MercatorTiledImageLayer;
     }
 );

src/layer/RestTiledImageLayer.js

@@ -72,7 +72,7 @@ define([
         var RestTiledImageLayer = function (serverAddress, pathToData, displayName, configuration) {
             var cachePath = WWUtil.urlPath(serverAddress + "/" + pathToData);
 
-            TiledImageLayer.call(this,
+            TiledImageLayer.call(this, displayName,
                 (configuration && configuration.sector) || Sector.FULL_SPHERE,
                 (configuration && configuration.levelZeroTileDelta) || new Location(45, 45),
                 (configuration && configuration.numLevels) || 5,
@@ -81,8 +81,6 @@ define([
                 (configuration && configuration.tileWidth) || 256,
                 (configuration && configuration.tileHeight) || 256);
 
-            this.displayName = displayName;
-            this.pickEnabled = false;
             this.urlBuilder = new LevelRowColumnUrlBuilder(serverAddress, pathToData);
         };
 

src/layer/TiledImageLayer.js

@@ -73,6 +73,7 @@ define([
          * Layers of this type are by default not pickable. Their pick-enabled flag is initialized to false.
          *
          * @augments Layer
+         * @param {String} displayName This layer's display name.
          * @param {Sector} sector The sector this layer covers.
          * @param {Location} levelZeroDelta The size in latitude and longitude of level zero (lowest resolution) tiles.
          * @param {Number} numLevels The number of levels to define for the layer. Each level is successively one power
@@ -87,7 +88,7 @@ define([
          * null or undefined, or if the specified number of levels, tile width or tile height is less than 1.
          *
          */
-        var TiledImageLayer = function (sector, levelZeroDelta, numLevels, imageFormat, cachePath, tileWidth, tileHeight) {
+        var TiledImageLayer = function (displayName, sector, levelZeroDelta, numLevels, imageFormat, cachePath, tileWidth, tileHeight) {
             if (!sector) {
                 throw new ArgumentError(
                     Logger.logMessage(Logger.LEVEL_SEVERE, "TiledImageLayer", "constructor", "missingSector"));
@@ -123,7 +124,7 @@ define([
                         "The specified tile width or height is less than one."));
             }
 
-            Layer.call(this, "Tiled Image Layer");
+            Layer.call(this, displayName || "Tiled Image Layer");
 
             this.retrievalImageFormat = imageFormat;
             this.cachePath = cachePath;

src/layer/WmsLayer.js

@@ -82,12 +82,9 @@ define([
                 cachePath = cachePath + timeString;
             }
 
-            TiledImageLayer.call(this, config.sector, config.levelZeroDelta, config.numLevels, config.format,
+            TiledImageLayer.call(this, config.title, config.sector, config.levelZeroDelta, config.numLevels, config.format,
                 cachePath, config.size, config.size);
 
-            this.displayName = config.title;
-            this.pickEnabled = false;
-
             this.urlBuilder = new WmsUrlBuilder(config.service, config.layerNames, config.styleNames, config.version,
                 timeString);
             if (config.coordinateSystem) {

src/layer/heatmap/HeatMapLayer.js

@@ -69,9 +69,7 @@ define([
         this.tileWidth = 256;
         this.tileHeight = 256;
 
-        TiledImageLayer.call(this, new Sector(-90, 90, -180, 180), new Location(45, 45), numLevels || 18, 'image/png', 'HeatMap' + WWUtil.guid(), this.tileWidth, this.tileHeight);
-
-        this.displayName = displayName;
+        TiledImageLayer.call(this, displayName, new Sector(-90, 90, -180, 180), new Location(45, 45), numLevels || 18, 'image/png', 'HeatMap' + WWUtil.guid(), this.tileWidth, this.tileHeight);
 
         var data = {};
         for (var lat = -90; lat <= 90; lat++) {