Separate first level delta in Level Set for latitude and longitude.

worldwind/src/main/java/gov/nasa/worldwind/globe/BasicTessellator.java

@@ -33,7 +33,7 @@
 public class BasicTessellator implements Tessellator, TileFactory {
 
     // ~0.6 meter resolution
-    protected LevelSet levelSet = new LevelSet(new Sector().setFullSphere(), new Location(-90, -180), 90, 20, 32, 32);
+    protected LevelSet levelSet = new LevelSet(new Sector().setFullSphere(), new Location(-90, -180), new Location(90, 90), 20, 32, 32);
 
     protected double detailControl = 80;
 

worldwind/src/main/java/gov/nasa/worldwind/layer/BlueMarbleLandsatLayer.java

@@ -85,7 +85,7 @@ public BlueMarbleLandsatLayer(String serviceAddress) {
 
     @Override
     public Tile createTile(Sector sector, Level level, int row, int column) {
-        double radiansPerPixel = Math.toRadians(level.tileDelta) / level.tileHeight;
+        double radiansPerPixel = Math.toRadians(level.tileDelta.latitude) / level.tileHeight;
         double metersPerPixel = radiansPerPixel * WorldWind.WGS84_SEMI_MAJOR_AXIS;
 
         if (metersPerPixel < 2.0e3) { // switch to Landsat at 2km resolution

worldwind/src/main/java/gov/nasa/worldwind/layer/LayerFactory.java

@@ -280,7 +280,10 @@ protected void createFromGeoPackageAsync(String pathName, Layer layer, Callback
                     tileMatrixSet.getMaxY() - tileMatrixSet.getMinY(),
                     tileMatrixSet.getMaxX() - tileMatrixSet.getMinX());
             config.tileOrigin.set(tileMatrixSet.getMinY(), tileMatrixSet.getMinX());
-            config.firstLevelDelta = (tileMatrixSet.getMaxY() - tileMatrixSet.getMinY()) / tileMatrix.valueAt(0).getMatrixHeight();
+            config.firstLevelDelta.set(
+                (tileMatrixSet.getMaxY() - tileMatrixSet.getMinY()) / tileMatrix.valueAt(0).getMatrixHeight(),
+                (tileMatrixSet.getMaxX() - tileMatrixSet.getMinX()) / tileMatrix.valueAt(0).getMatrixWidth()
+            );
             config.numLevels = tileMatrix.keyAt(tileMatrix.size() - 1) - tileMatrix.keyAt(0) + 1;
 
             TiledSurfaceImage surfaceImage = new TiledSurfaceImage();
@@ -681,7 +684,7 @@ protected LevelSet createWmtsLevelSet(WmtsLayer wmtsLayer, CompatibleTileMatrixS
         }
         int imageSize = tileMatrixSet.getTileMatrices().get(0).getTileHeight();
 
-        return new LevelSet(boundingBox, new Location(-90, -180), 90, compatibleTileMatrixSet.tileMatrices.size(), imageSize, imageSize);
+        return new LevelSet(boundingBox, new Location(-90, -180), new Location(90, 90), compatibleTileMatrixSet.tileMatrices.size(), imageSize, imageSize);
     }
 
     protected String buildWmtsKvpTemplate(String kvpServiceAddress, String layer, String format, String styleIdentifier, String tileMatrixSet) {

worldwind/src/main/java/gov/nasa/worldwind/layer/mercator/MercatorImageTile.java

@@ -53,8 +53,8 @@ static void assembleMercatorTilesForLevel(Level level, TileFactory tileFactory,
         // NOTE LevelSet.sector is final Sector attribute and thus can not be cast to MercatorSector!
         MercatorSector sector = MercatorSector.fromSector(level.parent.sector);
         Location tileOrigin = level.parent.tileOrigin;
-        double dLat = level.tileDelta / 2;
-        double dLon = level.tileDelta;
+        double dLat = level.tileDelta.latitude;
+        double dLon = level.tileDelta.longitude;
 
         int firstRow = Tile.computeRow(dLat, sector.minLatitude(), tileOrigin.latitude);
         int lastRow = Tile.computeLastRow(dLat, sector.maxLatitude(), tileOrigin.latitude);

worldwind/src/main/java/gov/nasa/worldwind/layer/mercator/MercatorTiledImageLayer.java

@@ -22,10 +22,12 @@ public MercatorTiledImageLayer(String name, int numLevels, int firstLevelOffset,
         this.setPickEnabled(false);
         this.firstLevelOffset = firstLevelOffset;
 
+        MercatorSector sector = MercatorSector.fromDegrees(-1.0, 1.0, - FULL_SPHERE / 2, FULL_SPHERE / 2);
+        Location tileOrigin = new Location(sector.minLatitude(), sector.minLongitude());
+        int n = 1 << firstLevelOffset;
+        Location firstLevelDelta = new Location(sector.deltaLatitude() / n, sector.deltaLongitude() / n);
         MercatorTiledSurfaceImage surfaceImage = new MercatorTiledSurfaceImage();
-        surfaceImage.setLevelSet(new LevelSet(
-                MercatorSector.fromDegrees(-1.0, 1.0, - FULL_SPHERE / 2, FULL_SPHERE / 2), new Location(-90, -180),
-                FULL_SPHERE / (1 << firstLevelOffset), numLevels - firstLevelOffset, tileSize, tileSize));
+        surfaceImage.setLevelSet(new LevelSet(sector, tileOrigin, firstLevelDelta, numLevels - firstLevelOffset, tileSize, tileSize));
         surfaceImage.setTileFactory(this);
         if(!overlay) {
             surfaceImage.setImageOptions(new ImageOptions(WorldWind.RGB_565)); // reduce memory usage by using a 16-bit configuration with no alpha

worldwind/src/main/java/gov/nasa/worldwind/util/Level.java

@@ -5,6 +5,8 @@
 
 package gov.nasa.worldwind.util;
 
+import gov.nasa.worldwind.geom.Location;
+
 /**
  * Represents a level of a specific resolution in a {@link LevelSet}.
  */
@@ -35,7 +37,7 @@ public class Level {
     /**
      * The geographic width and height in degrees of tiles within this level.
      */
-    public final double tileDelta;
+    public final Location tileDelta;
 
     /**
      * The parent LevelSet's tileWidth.
@@ -54,21 +56,21 @@ public class Level {
      * @param levelNumber the level's ordinal within its parent level set
      * @param tileDelta   the geographic width and height in degrees of tiles within this level
      */
-    public Level(LevelSet parent, int levelNumber, double tileDelta) {
+    public Level(LevelSet parent, int levelNumber, Location tileDelta) {
         if (parent == null) {
             throw new IllegalArgumentException(
                 Logger.logMessage(Logger.ERROR, "Level", "constructor", "The parent level set is null"));
         }
 
-        if (tileDelta <= 0) {
+        if (tileDelta == null || tileDelta.latitude <= 0 || tileDelta.longitude <= 0) {
             throw new IllegalArgumentException(
                 Logger.logMessage(Logger.ERROR, "Level", "constructor", "The tile delta is zero"));
         }
 
         this.parent = parent;
         this.levelNumber = levelNumber;
-        this.levelWidth = (int) Math.round(parent.tileWidth * parent.sector.deltaLongitude() / tileDelta);
-        this.levelHeight = (int) Math.round(parent.tileHeight * parent.sector.deltaLatitude() / tileDelta);
+        this.levelWidth = (int) Math.round(parent.tileWidth * parent.sector.deltaLongitude() / tileDelta.longitude);
+        this.levelHeight = (int) Math.round(parent.tileHeight * parent.sector.deltaLatitude() / tileDelta.latitude);
         this.tileDelta = tileDelta;
         this.tileWidth = parent.tileWidth;
         this.tileHeight = parent.tileHeight;

worldwind/src/main/java/gov/nasa/worldwind/util/LevelSet.java

@@ -25,9 +25,9 @@ public class LevelSet {
     public final Location tileOrigin = new Location();
 
     /**
-     * The geographic width and height in degrees of tiles in the first level (lowest resolution) of this level set.
+     * The geographic width and height in degrees of tiles in the first level (the lowest resolution) of this level set.
      */
-    public final double firstLevelDelta;
+    public final Location firstLevelDelta = new Location();
 
     /**
      * The width in pixels of images associated with tiles in this level set, or the number of sample points in the
@@ -51,7 +51,6 @@ public class LevelSet {
      * <code>firstLevel</code> and <code>lastLevel</code> always return null.
      */
     public LevelSet() {
-        this.firstLevelDelta = 0;
         this.tileWidth = 0;
         this.tileHeight = 0;
         this.levels = new Level[0];
@@ -74,7 +73,7 @@ public LevelSet() {
      *
      * @throws IllegalArgumentException If any argument is null, or if any dimension is zero
      */
-    public LevelSet(Sector sector, Location tileOrigin, double firstLevelDelta, int numLevels, int tileWidth, int tileHeight) {
+    public LevelSet(Sector sector, Location tileOrigin, Location firstLevelDelta, int numLevels, int tileWidth, int tileHeight) {
         if (sector == null) {
             throw new IllegalArgumentException(
                 Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "missingSector"));
@@ -85,7 +84,7 @@ public LevelSet(Sector sector, Location tileOrigin, double firstLevelDelta, int
                     Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "missingTileOrigin"));
         }
 
-        if (firstLevelDelta <= 0) {
+        if (firstLevelDelta == null || firstLevelDelta.latitude <= 0 || firstLevelDelta.longitude <= 0) {
             throw new IllegalArgumentException(
                 Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "invalidTileDelta"));
         }
@@ -102,7 +101,7 @@ public LevelSet(Sector sector, Location tileOrigin, double firstLevelDelta, int
 
         this.sector.set(sector);
         this.tileOrigin.set(tileOrigin);
-        this.firstLevelDelta = firstLevelDelta;
+        this.firstLevelDelta.set(firstLevelDelta);
         this.tileWidth = tileWidth;
         this.tileHeight = tileHeight;
         this.levels = new Level[numLevels];
@@ -129,12 +128,7 @@ public LevelSet(LevelSetConfig config) {
                 Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "missingSector"));
         }
 
-        if (config.tileOrigin == null) {
-            throw new IllegalArgumentException(
-                    Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "missingTileOrigin"));
-        }
-
-        if (config.firstLevelDelta <= 0) {
+        if (config.firstLevelDelta.latitude <= 0 || config.firstLevelDelta.longitude <= 0) {
             throw new IllegalArgumentException(
                 Logger.logMessage(Logger.ERROR, "LevelSet", "constructor", "invalidTileDelta"));
         }
@@ -151,7 +145,7 @@ public LevelSet(LevelSetConfig config) {
 
         this.sector.set(config.sector);
         this.tileOrigin.set(config.tileOrigin);
-        this.firstLevelDelta = config.firstLevelDelta;
+        this.firstLevelDelta.set(config.firstLevelDelta);
         this.tileWidth = config.tileWidth;
         this.tileHeight = config.tileHeight;
         this.levels = new Level[config.numLevels];
@@ -160,7 +154,8 @@ public LevelSet(LevelSetConfig config) {
 
     protected void assembleLevels() {
         for (int i = 0, len = this.levels.length; i < len; i++) {
-            double delta = firstLevelDelta / (1 << i);
+            int n = 1 << i;
+            Location delta = new Location(firstLevelDelta.latitude / n, firstLevelDelta.longitude / n);
             this.levels[i] = new Level(this, i, delta);
         }
     }
@@ -209,7 +204,7 @@ public Level levelForResolution(double radiansPerPixel) {
         }
 
         double degreesPerPixel = Math.toDegrees(radiansPerPixel);
-        double firstLevelDegreesPerPixel = this.firstLevelDelta / Math.min(this.tileWidth, this.tileHeight);
+        double firstLevelDegreesPerPixel = Math.max(this.firstLevelDelta.longitude / this.tileWidth, this.firstLevelDelta.latitude / this.tileHeight);
         double level = Math.log(firstLevelDegreesPerPixel / degreesPerPixel) / Math.log(2); // fractional level address
         int levelNumber = (int) Math.round(level); // nearest neighbor level
 

worldwind/src/main/java/gov/nasa/worldwind/util/LevelSetConfig.java

@@ -25,9 +25,9 @@ public class LevelSetConfig {
     public final Location tileOrigin = new Location(-90, -180);
 
     /**
-     * The geographic width and height in degrees of tiles in the first level (lowest resolution) of the level set.
+     * The geographic width and height in degrees of tiles in the first level (the lowest resolution) of the level set.
      */
-    public double firstLevelDelta = 90;
+    public final Location firstLevelDelta = new Location(90, 90);
 
     /**
      * The number of levels in the level set.
@@ -69,12 +69,12 @@ public LevelSetConfig() {
      *                        sample points in the latitudinal direction of elevation tiles associate with the level
      *                        set
      */
-    public LevelSetConfig(Sector sector, double firstLevelDelta, int numLevels, int tileWidth, int tileHeight) {
+    public LevelSetConfig(Sector sector, Location firstLevelDelta, int numLevels, int tileWidth, int tileHeight) {
         if (sector != null) {
             this.sector.set(sector);
         }
 
-        this.firstLevelDelta = firstLevelDelta;
+        this.firstLevelDelta.set(firstLevelDelta);
         this.numLevels = numLevels;
         this.tileWidth = tileWidth;
         this.tileHeight = tileHeight;
@@ -97,7 +97,7 @@ public int numLevelsForResolution(double radiansPerPixel) {
         }
 
         double degreesPerPixel = Math.toDegrees(radiansPerPixel);
-        double firstLevelDegreesPerPixel = this.firstLevelDelta / Math.min(this.tileWidth, this.tileHeight);
+        double firstLevelDegreesPerPixel = Math.max(this.firstLevelDelta.longitude / this.tileWidth, this.firstLevelDelta.latitude / this.tileHeight);
         double level = Math.log(firstLevelDegreesPerPixel / degreesPerPixel) / Math.log(2); // fractional level address
         int levelNumber = (int) Math.ceil(level); // ceiling captures the resolution
 
@@ -126,7 +126,7 @@ public int numLevelsForMinResolution(double radiansPerPixel) {
         }
 
         double degreesPerPixel = Math.toDegrees(radiansPerPixel);
-        double firstLevelDegreesPerPixel = this.firstLevelDelta / this.tileHeight;
+        double firstLevelDegreesPerPixel = Math.max(this.firstLevelDelta.longitude / this.tileWidth, this.firstLevelDelta.latitude / this.tileHeight);
         double level = Math.log(firstLevelDegreesPerPixel / degreesPerPixel) / Math.log(2); // fractional level address
         int levelNumber = (int) Math.floor(level); // floor prevents exceeding the min scale
 

worldwind/src/main/java/gov/nasa/worldwind/util/Tile.java

@@ -109,7 +109,7 @@ public Tile(Sector sector, Level level, int row, int column) {
         this.row = row;
         this.column = column;
         this.tileKey = level.levelNumber + "." + row + "." + column;
-        this.texelSizeFactor = Math.toRadians(level.tileDelta / level.tileWidth) * Math.cos(Math.toRadians(sector.centroidLatitude()));
+        this.texelSizeFactor = Math.toRadians(level.tileDelta.longitude / level.tileWidth) * Math.cos(Math.toRadians(sector.centroidLatitude()));
     }
 
     /**
@@ -217,29 +217,29 @@ public static Collection<Tile> assembleTilesForLevel(Level level, TileFactory ti
 
         Sector sector = level.parent.sector;
         Location tileOrigin = level.parent.tileOrigin;
-        double tileDelta = level.tileDelta;
+        Location tileDelta = level.tileDelta;
 
-        int firstRow = Tile.computeRow(tileDelta, sector.minLatitude(), tileOrigin.latitude);
-        int lastRow = Tile.computeLastRow(tileDelta, sector.maxLatitude(), tileOrigin.latitude);
-        int firstCol = Tile.computeColumn(tileDelta, sector.minLongitude(), tileOrigin.longitude);
-        int lastCol = Tile.computeLastColumn(tileDelta, sector.maxLongitude(), tileOrigin.longitude);
+        int firstRow = Tile.computeRow(tileDelta.latitude, sector.minLatitude(), tileOrigin.latitude);
+        int lastRow = Tile.computeLastRow(tileDelta.latitude, sector.maxLatitude(), tileOrigin.latitude);
+        int firstCol = Tile.computeColumn(tileDelta.longitude, sector.minLongitude(), tileOrigin.longitude);
+        int lastCol = Tile.computeLastColumn(tileDelta.longitude, sector.maxLongitude(), tileOrigin.longitude);
 
-        double firstRowLat = tileOrigin.latitude + firstRow * tileDelta;
-        double firstRowLon = tileOrigin.longitude + firstCol * tileDelta;
+        double firstRowLat = tileOrigin.latitude + firstRow * tileDelta.latitude;
+        double firstRowLon = tileOrigin.longitude + firstCol * tileDelta.longitude;
         double lat = firstRowLat;
         double lon;
 
         for (int row = firstRow; row <= lastRow; row++) {
             lon = firstRowLon;
 
             for (int col = firstCol; col <= lastCol; col++) {
-                Sector tileSector = new Sector(lat, lon, tileDelta, tileDelta);
+                Sector tileSector = new Sector(lat, lon, tileDelta.latitude, tileDelta.longitude);
                 result.add(tileFactory.createTile(tileSector, level, row, col));
 
-                lon += tileDelta;
+                lon += tileDelta.longitude;
             }
 
-            lat += tileDelta;
+            lat += tileDelta.latitude;
         }
 
         return result;
@@ -334,26 +334,27 @@ public Tile[] subdivide(TileFactory tileFactory) {
         double lonMin = this.sector.minLongitude();
         double latMid = this.sector.centroidLatitude();
         double lonMid = this.sector.centroidLongitude();
-        double childDelta = this.level.tileDelta * 0.5;
+        double childDeltaLat = this.level.tileDelta.latitude * 0.5;
+        double childDeltaLon = this.level.tileDelta.longitude * 0.5;
 
         int childRow = 2 * this.row;
         int childCol = 2 * this.column;
-        Sector childSector = new Sector(latMin, lonMin, childDelta, childDelta);
+        Sector childSector = new Sector(latMin, lonMin, childDeltaLat, childDeltaLon);
         children[0] = tileFactory.createTile(childSector, childLevel, childRow, childCol); // Southwest
 
         childRow = 2 * this.row;
         childCol = 2 * this.column + 1;
-        childSector = new Sector(latMin, lonMid, childDelta, childDelta);
+        childSector = new Sector(latMin, lonMid, childDeltaLat, childDeltaLon);
         children[1] = tileFactory.createTile(childSector, childLevel, childRow, childCol); // Southeast
 
         childRow = 2 * this.row + 1;
         childCol = 2 * this.column;
-        childSector = new Sector(latMid, lonMin, childDelta, childDelta);
+        childSector = new Sector(latMid, lonMin, childDeltaLat, childDeltaLon);
         children[2] = tileFactory.createTile(childSector, childLevel, childRow, childCol); // Northwest
 
         childRow = 2 * this.row + 1;
         childCol = 2 * this.column + 1;
-        childSector = new Sector(latMid, lonMid, childDelta, childDelta);
+        childSector = new Sector(latMid, lonMid, childDeltaLat, childDeltaLon);
         children[3] = tileFactory.createTile(childSector, childLevel, childRow, childCol); // Northeast
 
         return children;

worldwind/src/test/java/gov/nasa/worldwind/globe/BasicTerrainTest.java

@@ -82,7 +82,7 @@ public void setUp() {
         this.terrain = new BasicTerrain();
 
         // Add a terrain tile used to the mocked terrain
-        LevelSet levelSet = new LevelSet(new Sector().setFullSphere(), new Location(-90, -180), 1.0, 1, 5, 5); // tiles with 5x5 vertices
+        LevelSet levelSet = new LevelSet(new Sector().setFullSphere(), new Location(-90, -180), new Location(1.0, 1.0), 1, 5, 5); // tiles with 5x5 vertices
         TerrainTile tile = new TerrainTile(new Sector(0, 0, 1, 1), levelSet.firstLevel(), 90, 180);
         ((BasicTerrain) this.terrain).addTile(tile);