Geodan · bertt · Feb 26, 2025
diff --git a/README.md b/README.md
@@ -212,6 +212,8 @@ If --username and/or --dbname are not specified the current username is used as
 
   --skip_create_tiles             (Default: false) Skip creating tiles (Cesium)
 
+  --enable_zoom_features          (Default: false) Creates extra tiles on lower zoom levels containing larger features (Cesium)
+
   --zoom                          (Default: 15) Zoom level (Mapbox)
 
   --help                          Display this help screen.

diff --git a/src/b3dm.tileset/CesiumTiler.cs b/src/b3dm.tileset/CesiumTiler.cs
@@ -10,7 +10,7 @@
 namespace B3dm.Tileset;
 public static class CesiumTiler
 {
-    public static void CreateImplicitTileset(Version version, bool createGltf, string outputDirectory, double[] translation, double geometricError, double[] rootBoundingVolumeRegion, string subtreesDirectory, List<Tile> tiles, string tilesetVersion="")
+    public static void CreateImplicitTileset(Version version, bool createGltf, string outputDirectory, double[] translation, double geometricError, double[] rootBoundingVolumeRegion, string subtreesDirectory, List<Tile> tiles, string tilesetVersion="", string refinement="")
     {
         if (!Directory.Exists(subtreesDirectory)) {
             Directory.CreateDirectory(subtreesDirectory);
@@ -28,7 +28,7 @@ public static void CreateImplicitTileset(Version version, bool createGltf, strin
         var availableLevels = tiles.Max(t => t.Z) + 1;
         Console.WriteLine("Available Levels: " + availableLevels);
         Console.WriteLine("Subtree Levels: " + subtreeLevels);
-        var tilesetjson = TreeSerializer.ToImplicitTileset(translation, rootBoundingVolumeRegion, geometricError, availableLevels, subtreeLevels, version, createGltf, tilesetVersion);
+        var tilesetjson = TreeSerializer.ToImplicitTileset(translation, rootBoundingVolumeRegion, geometricError, availableLevels, subtreeLevels, version, createGltf, tilesetVersion, refinement);
         var file = $"{outputDirectory}{Path.AltDirectorySeparatorChar}tileset.json";
         var json = JsonConvert.SerializeObject(tilesetjson, Formatting.Indented, new JsonSerializerSettings() { NullValueHandling = NullValueHandling.Ignore });
         Console.WriteLine("SubdivisionScheme: QUADTREE");

diff --git a/src/b3dm.tileset/GeometryRepository.cs b/src/b3dm.tileset/GeometryRepository.cs
@@ -37,15 +37,15 @@ public static double[] GetGeometriesBoundingBox(NpgsqlConnection conn, string ge
         return result;
     }
 
-    public static List<GeometryRecord> GetGeometrySubset(NpgsqlConnection conn, string geometry_table, string geometry_column, double[] bbox, int source_epsg, int target_srs, string shaderColumn = "", string attributesColumns = "", string query = "", string radiusColumn = "")
+    public static List<GeometryRecord> GetGeometrySubset(NpgsqlConnection conn, string geometry_table, string geometry_column, double[] bbox, int source_epsg, int target_srs, string shaderColumn = "", string attributesColumns = "", string query = "", string radiusColumn = "", string sqlPostFix = "")
     {
         var sqlselect = GetSqlSelect(geometry_column, shaderColumn, attributesColumns, radiusColumn, target_srs);
         var sqlFrom = "FROM " + geometry_table;
 
         var b = GetTileBoundingBox(bbox);
 
         var sqlWhere = GetWhere(geometry_column, source_epsg, b.xmin, b.ymin, b.xmax, b.ymax, query);
-        var sql = sqlselect + sqlFrom + sqlWhere;
+        var sql = sqlselect + sqlFrom + sqlWhere + sqlPostFix ;
 
         var geometries = GetGeometries(conn, shaderColumn, attributesColumns, sql, radiusColumn);
         return geometries;

diff --git a/src/b3dm.tileset/QuadtreeTiler.cs b/src/b3dm.tileset/QuadtreeTiler.cs
@@ -16,6 +16,7 @@ public class QuadtreeTiler
     private readonly string table;
     private readonly NpgsqlConnection conn;
     private readonly int source_epsg;
+    private readonly int target_srs;
     private readonly string geometryColumn;
     private readonly int maxFeaturesPerTile;
     private readonly string query;
@@ -29,11 +30,12 @@ public class QuadtreeTiler
     private readonly bool skipCreateTiles;
     private readonly string radiusColumn;
 
-    public QuadtreeTiler(NpgsqlConnection conn, string table, int source_epsg, string geometryColumn, int maxFeaturesPerTile, string query, double[] translation, string colorColumn, string attributesColumn, string lodColumn, string outputFolder, List<int> lods, string copyright = "", bool skipCreateTiles = false, string radiusColumn = "")
+    public QuadtreeTiler(NpgsqlConnection conn, string table, int source_epsg, int target_srs, string geometryColumn, int maxFeaturesPerTile, string query, double[] translation, string colorColumn, string attributesColumn, string lodColumn, string outputFolder, List<int> lods, string copyright = "", bool skipCreateTiles = false, string radiusColumn = "")
     {
         this.table = table;
         this.conn = conn;
         this.source_epsg = source_epsg;
+        this.target_srs = target_srs;
         this.geometryColumn = geometryColumn;
         this.maxFeaturesPerTile = maxFeaturesPerTile;
         this.query = query;
@@ -89,19 +91,10 @@ public List<Tile> GenerateTiles(BoundingBox bbox, Tile tile, List<Tile> tiles, i
             }
         }
         else {
-
-            var file = $"{tile.Z}_{tile.X}_{tile.Y}";
-            if (lodColumn != String.Empty) {
-                file += $"_{lod}";
-            }
-
-            var ext = createGltf ? ".glb" : ".b3dm";
-            file += ext;
+            var file = TileName.GetFileName(tile, createGltf, lodColumn, lod);
             Console.Write($"\rCreating tile: {file}  ");
             tile.ContentUri = file;
 
-            int target_srs = 4978;
-
             byte[] bytes = null;
 
             var geometries = GeometryRepository.GetGeometrySubset(conn, table, geometryColumn, tile.BoundingBox, source_epsg, target_srs, colorColumn, attributesColumn, where, radiusColumn);
@@ -125,7 +118,8 @@ public List<Tile> GenerateTiles(BoundingBox bbox, Tile tile, List<Tile> tiles, i
                         t2.BoundingBox = tile.BoundingBox;
                         var lodNextTiles = GenerateTiles(bbox, t2, new List<Tile>(), nextLod, addOutlines, defaultColor, defaultMetallicRoughness, doubleSided, defaultAlphaMode, createGltf);
                         tile.Children = lodNextTiles;
-                    };
+                    }
+                    ;
                 }
 
                 // next code is used to fix geometries that have centroid in the tile, but some parts outside...

diff --git a/src/b3dm.tileset/TileName.cs b/src/b3dm.tileset/TileName.cs
@@ -0,0 +1,21 @@
+using System;
+using subtree;
+
+namespace B3dm.Tileset
+{
+    public static class TileName
+    {
+        public static string GetFileName(Tile tile, bool createGltf, string lodColumn1 = "", int? lod = null)
+        {
+            var file = $"{tile.Z}_{tile.X}_{tile.Y}";
+            if (lodColumn1 != String.Empty) {
+                file += $"_{lod}";
+            }
+
+            var ext = createGltf ? ".glb" : ".b3dm";
+            file += ext;
+            return file;
+        }
+
+    }
+}
diff --git a/src/b3dm.tileset/TreeSerializer.cs b/src/b3dm.tileset/TreeSerializer.cs
@@ -1,7 +1,6 @@
 using System;
 using System.Collections.Generic;
 using System.IO;
-using System.Linq;
 using B3dm.Tileset.Extensions;
 using subtree;
 using Wkx;
@@ -10,7 +9,7 @@ namespace B3dm.Tileset;
 
 public static class TreeSerializer
 {
-    public static TileSet ToImplicitTileset(double[] transform, double[] box, double maxGeometricError, int availableLevels, int subtreeLevels, Version version = null, bool createGltf = false, string tilesetVersion = "")
+    public static TileSet ToImplicitTileset(double[] transform, double[] box, double maxGeometricError, int availableLevels, int subtreeLevels, Version version = null, bool createGltf = false, string tilesetVersion = "", string refine = "")
     {
         var ext = createGltf ? ".glb" : ".b3dm";
         var geometricError = maxGeometricError;
@@ -19,7 +18,7 @@ public static TileSet ToImplicitTileset(double[] transform, double[] box, double
                                  0.0,1.0, 0.0, 0.0,
                                  0.0, 0.0, 1.0, 0.0,
             transform[0], transform[1], transform[2], 1.0};
-        var root = GetRoot(geometricError, t, box);
+        var root = GetRoot(geometricError, t, box,refine);
         var content = new Content() { uri = "content/{level}_{x}_{y}" + ext };
         root.content = content;
         var subtrees = new Subtrees() { uri = "subtrees/{level}_{x}_{y}.subtree" };

diff --git a/src/pg2b3dm.database.tests/UnitTest1.cs b/src/pg2b3dm.database.tests/UnitTest1.cs
@@ -65,7 +65,7 @@ public void ImplicitTilingTest()
         var center_wgs84 = bbox_wgs84.bbox.GetCenter();
         var translation = SpatialConverter.GeodeticToEcef((double)center_wgs84.X!, (double)center_wgs84.Y!, 0);
         var trans = new double[] { translation.X, translation.Y, translation.Z };
-        var implicitTiler = new QuadtreeTiler(conn, "delaware_buildings", 4326, "geom_triangle", 50, string.Empty,
+        var implicitTiler = new QuadtreeTiler(conn, "delaware_buildings", 4326, 4978, "geom_triangle", 50, string.Empty,
             trans,
             "shaders",
             string.Empty,
@@ -93,7 +93,7 @@ public void LodTest()
         var translation = SpatialConverter.GeodeticToEcef((double)center_wgs84.X!, (double)center_wgs84.Y!, 0);
         var trans = new double[] { translation.X, translation.Y, translation.Z };
 
-        var implicitTiler = new QuadtreeTiler(conn, "delaware_buildings_lod", 4326, "geom_triangle", 10, string.Empty,
+        var implicitTiler = new QuadtreeTiler(conn, "delaware_buildings_lod", 4326, 4978, "geom_triangle", 10, string.Empty,
             trans,
             "shaders",
             string.Empty,
@@ -119,7 +119,7 @@ public void GeometryTest()
         var center_wgs84 = bbox_wgs84.bbox.GetCenter();
         var translation = SpatialConverter.GeodeticToEcef((double)center_wgs84.X!, (double)center_wgs84.Y!, 0);
         var trans = new double[] { translation.X, translation.Y, translation.Z };
-        var implicitTiler = new QuadtreeTiler(conn, "geom_test", 4326, "geom3d", 50, string.Empty,
+        var implicitTiler = new QuadtreeTiler(conn, "geom_test", 4326, 4978, "geom3d", 50, string.Empty,
             trans,
             string.Empty,
             string.Empty,

diff --git a/src/pg2b3dm/Options.cs b/src/pg2b3dm/Options.cs
@@ -81,7 +81,8 @@ public class Options
     [Option("skip_create_tiles", Required = false, Default = false, HelpText = "Skip creating tiles, only create tileset.json files (Cesium)", SetName = "Cesium")]
     public bool SkipCreateTiles { get; set; }
 
-
+    [Option("enable_zoom_features", Required = false, Default = false, HelpText = "Creates extra tiles on lower zoom levels containing larger features", SetName = "Cesium")]
+    public bool EnableZoomFeatures{ get; set; }
     // mapbox specific options
     [Option("zoom", Required = false, Default = 15, HelpText = "Zoom level (Mapbox)", SetName = "Mapbox")]
     public int Zoom { get; set; }

diff --git a/src/pg2b3dm/Program.cs b/src/pg2b3dm/Program.cs
@@ -117,6 +117,7 @@ static void Main(string[] args)
             Console.WriteLine($"Doublesided: {doubleSided}");
             Console.WriteLine($"Default AlphaMode: {defaultAlphaMode}");
             Console.WriteLine($"Create glTF tiles: {createGltf}");
+            Console.WriteLine($"Enable zoom features: {o.EnableZoomFeatures}");
 
             var att = !string.IsNullOrEmpty(o.AttributeColumns) ? o.AttributeColumns : "-";
             Console.WriteLine($"Attribute columns: {att}");
@@ -175,16 +176,42 @@ static void Main(string[] args)
                 Console.WriteLine($"Maximum features per tile: " + o.MaxFeaturesPerTile);
 
                 var tile = new Tile(0, 0, 0);
+                var target_srs = 4978;
                 tile.BoundingBox = bbox.ToArray();
                 Console.WriteLine($"Start generating tiles...");
-                var quadtreeTiler = new QuadtreeTiler(conn, table, source_epsg, geometryColumn, o.MaxFeaturesPerTile, query, translation, o.ShadersColumn, o.AttributeColumns, lodcolumn, contentDirectory, lods, o.Copyright, skipCreateTiles, o.RadiusColumn);
+                var quadtreeTiler = new QuadtreeTiler(conn, table, source_epsg, target_srs, geometryColumn, o.MaxFeaturesPerTile, query, translation, o.ShadersColumn, o.AttributeColumns, lodcolumn, contentDirectory, lods, o.Copyright, skipCreateTiles, o.RadiusColumn);
                 var tiles = quadtreeTiler.GenerateTiles(bbox, tile, new List<Tile>(), lodcolumn != string.Empty ? lods.First() : 0, addOutlines, defaultColor, defaultMetallicRoughness, doubleSided, defaultAlphaMode, createGltf);
                 Console.WriteLine();
                 Console.WriteLine("Tiles created: " + tiles.Count(tile => tile.Available));
 
+
+                if (o.EnableZoomFeatures) {
+                    var level_min = tiles.Where(tiles => tiles.Available).Min(t => t.Z);
+                    var level_max = tiles.Where(tiles => tiles.Available).Max(t => t.Z);
+
+                    var extraTiles = new List<Tile>();
+                    foreach (var t in tiles) {
+                        if (!t.Available && t.Z >= level_min && t.Z < level_max) {
+                            var fileName = TileName.GetFileName(t, createGltf);
+                            Console.Write($"\rCreating extra tile: {fileName}");
+                            var postfixSql = $" ORDER BY ST_Area({geometryColumn}) DESC LIMIT {o.MaxFeaturesPerTile}";
+                            var geometries = GeometryRepository.GetGeometrySubset(conn, table, geometryColumn, tile.BoundingBox, source_epsg, target_srs, o.ShadersColumn, o.AttributeColumns, where, o.RadiusColumn, postfixSql);
+                            var bytes = TileWriter.ToTile(geometries, translation, copyright: copyright, addOutlines: addOutlines, defaultColor: defaultColor, defaultMetallicRoughness: defaultMetallicRoughness, doubleSided: doubleSided, defaultAlphaMode: defaultAlphaMode, createGltf: createGltf);
+                            File.WriteAllBytes($"{contentDirectory}{Path.AltDirectorySeparatorChar}{fileName}", bytes);
+                            t.Available = true;
+                            extraTiles.Add(t);
+                        }
+                    }
+                    Console.WriteLine();
+                    Console.WriteLine("Extra tiles created: " + extraTiles.Count);
+
+                    tiles.AddRange(extraTiles);
+                }
+
+
                 if (tiles.Count(tile => tile.Available) > 0) {
                     if (useImplicitTiling) {
-                        CesiumTiler.CreateImplicitTileset(version, createGltf, outputDirectory, translation, o.GeometricError, rootBoundingVolumeRegion, subtreesDirectory, tiles, tilesetVersion);
+                        CesiumTiler.CreateImplicitTileset(version, createGltf, outputDirectory, translation, o.GeometricError, rootBoundingVolumeRegion, subtreesDirectory, tiles, tilesetVersion, refinement);
                     }
                     else {
                         CesiumTiler.CreateExplicitTilesetsJson(version, outputDirectory, translation, o.GeometricError, o.GeometricErrorFactor, refinement, use10, rootBoundingVolumeRegion, tile, tiles, tilesetVersion);