diff --git a/DATA_SuPER/DEM_SuPER.py b/DATA_SuPER/DEM_SuPER.py
index 737ba0a..ad54b95 100644
--- a/DATA_SuPER/DEM_SuPER.py
+++ b/DATA_SuPER/DEM_SuPER.py
@@ -22,7 +22,7 @@ Step2: Process DEM data
 
 -------------------------------------------------------------------------------                        
 Authors: Hong Xie
-Last Updated: 2025-07-03
+Last Updated: 2025-08-05
 ===============================================================================
 """
 
@@ -183,14 +183,14 @@ def process_granule(
                     dem.rio.write_crs("EPSG:4326", inplace=True)
                     dem.attrs["scale_factor"] = 1
                 dem_raster_list.append(dem)
-            if len(dem_raster_list) > 1:
+            if len(dem_raster_list) >= 1:
                 if name == "slope" or name == "aspect":
                     dem_mosaiced = mosaic_images(dem_raster_list, nodata=-9999)
                 else:
                     dem_mosaiced = mosaic_images(dem_raster_list, nodata=-32768)
-            if roi is not None and clip:
-                dem_mosaiced = clip_image(dem_mosaiced, roi)
-            dem_mosaiced.rio.to_raster(output_file, driver="COG", compress="DEFLATE")
+                if roi is not None and clip:
+                    dem_mosaiced = clip_image(dem_mosaiced, roi, clip_by_box=True)
+                dem_mosaiced.rio.to_raster(output_file, driver="COG", compress="DEFLATE")
         except Exception as e:
             logging.error(f"Error processing files in {name}: {e}")
             return False
@@ -211,6 +211,7 @@ def main(region: list, asset_name: list, tile_id: str):
     unzip_dir = os.path.join(download_dir, "UNZIP")
     output_dir = os.path.join(output_root_dir, "TIF", tile_id)
     os.makedirs(unzip_dir, exist_ok=True)
+    os.makedirs(output_dir, exist_ok=True)
     results_urls_file = f"{output_root_dir}\\NASADEM_{tile_id}_results_urls.json"
     if not os.path.isfile(results_urls_file):
         results_urls = earthdata_search(asset_name, roi=bbox)