Hadling possible issues with USGS portal

Author: jackdmarquez

hands-on/session II/1.Tutorial.ipynb

@@ -175,11 +175,15 @@
     "Path(hillshading_tiles).mkdir(parents=True, exist_ok=True)\n",
     "Path(slope_tiles).mkdir(parents=True, exist_ok=True)\n",
     "\n",
-    "gt.fetch_dem(\n",
-    "    bbox=region_bounding_box,\n",
-    "    txtPath=download_list,\n",
-    "    dataset=\"National Elevation Dataset (NED) 1 arc-second Current\",\n",
-    ")\n",
+    "try:\n",
+    "    gt.fetch_dem(\n",
+    "        bbox=region_bounding_box,\n",
+    "        txtPath=download_list,\n",
+    "        dataset=\"National Elevation Dataset (NED) 1 arc-second Current\",\n",
+    "    )\n",
+    "except Exception as e:\n",
+    "    print(\"USGS portal may be down right now, let's use another source\")\n",
+    "\n",
     "gt.download_files(download_list, tiles_folder)\n",
     "print(\"You have successfully downloaded the DEMs from USGS.\")"
    ]