More refactoring, move minimap behind facade

Logic/FeatureSource/TiledFeatureSource/TileHierarchy.ts

@@ -0,0 +1,25 @@
+import FeatureSource, {Tiled} from "../FeatureSource";
+import {BBox} from "../../GeoOperations";
+
+export default interface TileHierarchy<T extends FeatureSource & Tiled> {
+
+    /**
+     * A mapping from 'tile_index' to the actual tile featrues
+     */
+    loadedTiles: Map<number, T>
+
+}
+
+export class TileHierarchyTools {
+
+    public static getTiles<T extends FeatureSource & Tiled>(hierarchy: TileHierarchy<T>, bbox: BBox): T[] {
+        const result = []
+        hierarchy.loadedTiles.forEach((tile) => {
+            if (tile.bbox.overlapsWith(bbox)) {
+                result.push(tile)
+            }
+        })
+        return result;
+    }
+
+}