diff --git a/core/src/data/rasterSource.h b/core/src/data/rasterSource.h
index 073b297026..dba6ba147e 100644
--- a/core/src/data/rasterSource.h
+++ b/core/src/data/rasterSource.h
@@ -34,7 +34,7 @@ class RasterSource : public TileSource {
                  TextureOptions _options, bool genMipmap = false);
 
 
-    void loadTileData(std::shared_ptr<TileTask> _task, TileTaskCb _cb);
+    void loadTileData(std::shared_ptr<TileTask> _task, TileTaskCb _cb) override;
 
     virtual std::shared_ptr<TileTask> createTask(TileID _tile, int _subTask) override;