{
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   "source": [
    "# Downloading elevation data\n",
    "\n",
    "This short tutorial demonstrates how to download elevation data for specific areas using a library called `elevation`.\n",
    "`elevation` provides easy download, cache and access of the global datasets SRTM 30m Global 1 arc second V003 elaborated by NASA and NGA hosted on Amazon S3 and SRTM 90m Digital Elevation Database v4.1 elaborated by CGIAR-CSI.\n",
    "\n",
    "Let's first import required libraries:"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 4,
   "id": "4eca1eca",
   "metadata": {},
   "outputs": [],
   "source": [
    "import elevation\n",
    "import pathlib\n",
    "import osmnx as ox"
   ]
  },
  {
   "cell_type": "markdown",
   "id": "223cd8e8",
   "metadata": {},
   "source": [
    "## Elevation data for Helsinki"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 6,
   "id": "16e1a881",
   "metadata": {},
   "outputs": [
    {
     "name": "stderr",
     "output_type": "stream",
     "text": [
      "/home/hentenka/.conda/envs/mamba/envs/python-gis-book/lib/python3.9/site-packages/osmnx/geocoder.py:110: FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.\n",
      "  gdf = gdf.append(_geocode_query_to_gdf(q, wr, by_osmid))\n",
      "/home/hentenka/.conda/envs/mamba/envs/python-gis-book/lib/python3.9/site-packages/osmnx/geocoder.py:110: FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.\n",
      "  gdf = gdf.append(_geocode_query_to_gdf(q, wr, by_osmid))\n",
      "/home/hentenka/.conda/envs/mamba/envs/python-gis-book/lib/python3.9/site-packages/osmnx/geocoder.py:110: FutureWarning: The frame.append method is deprecated and will be removed from pandas in a future version. Use pandas.concat instead.\n",
      "  gdf = gdf.append(_geocode_query_to_gdf(q, wr, by_osmid))\n"
     ]
    },
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "make: Entering directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "curl -s -o spool/N59/N59E024.hgt.gz.temp https://s3.amazonaws.com/elevation-tiles-prod/skadi/N59/N59E024.hgt.gz && mv spool/N59/N59E024.hgt.gz.temp spool/N59/N59E024.hgt.gz\n",
      "gunzip spool/N59/N59E024.hgt.gz 2>/dev/null || touch spool/N59/N59E024.hgt\n",
      "gdal_translate -q -co TILED=YES -co COMPRESS=DEFLATE -co ZLEVEL=9 -co PREDICTOR=2 spool/N59/N59E024.hgt cache/N59/N59E024.tif 2>/dev/null || touch cache/N59/N59E024.tif\n",
      "curl -s -o spool/N59/N59E025.hgt.gz.temp https://s3.amazonaws.com/elevation-tiles-prod/skadi/N59/N59E025.hgt.gz && mv spool/N59/N59E025.hgt.gz.temp spool/N59/N59E025.hgt.gz\n",
      "gunzip spool/N59/N59E025.hgt.gz 2>/dev/null || touch spool/N59/N59E025.hgt\n",
      "gdal_translate -q -co TILED=YES -co COMPRESS=DEFLATE -co ZLEVEL=9 -co PREDICTOR=2 spool/N59/N59E025.hgt cache/N59/N59E025.tif 2>/dev/null || touch cache/N59/N59E025.tif\n",
      "rm spool/N59/N59E024.hgt spool/N59/N59E025.hgt\n",
      "make: Leaving directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "make: Entering directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "gdalbuildvrt -q -overwrite SRTM1.vrt cache/N59/N59E025.tif cache/N59/N59E024.tif cache/N50/N50E000.tif cache/N50/N50W001.tif cache/N60/N60E024.tif cache/N60/N60E025.tif cache/N51/N51W001.tif cache/N51/N51E000.tif\n",
      "make: Leaving directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "make: Entering directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "cp SRTM1.vrt SRTM1.6c58550bed364daaa292eb9b6cfd07ef.vrt\n",
      "make: Leaving directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "make: Entering directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "gdal_translate -q -co TILED=YES -co COMPRESS=DEFLATE -co ZLEVEL=9 -co PREDICTOR=2 -projwin 24.4992905 60.4013745 25.2545116 59.9010905 SRTM1.6c58550bed364daaa292eb9b6cfd07ef.vrt /home/hentenka/edu/FinEst-workshop/source/notebooks/data_access/Helsinki-DEM.tif\n",
      "rm -f SRTM1.6c58550bed364daaa292eb9b6cfd07ef.vrt\n",
      "make: Leaving directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "make: Entering directory '/home/hentenka/.cache/elevation/SRTM1'\n",
      "find cache -size 0 -name \"*.tif\" -delete\n",
      "rm -f SRTM1.*.vrt\n",
      "rm -f -r spool/*\n",
      "make: Leaving directory '/home/hentenka/.cache/elevation/SRTM1'\n"
     ]
    }
   ],
   "source": [
    "# Parse boundaries for Helsinki, Espoo and Vantaa\n",
    "helsinki = ox.geocoder.geocode_to_gdf([\"Helsinki\", \"Espoo\", \"Vantaa\"])\n",
    "bounds = helsinki.geometry.total_bounds\n",
    "\n",
    "# Output filepath (get a full path, i.e. absolute)\n",
    "outfp = pathlib.Path(\"Helsinki-DEM.tif\").absolute()\n",
    "\n",
    "# Get the elevation data for the area\n",
    "elevation.clip(bounds=bounds, output=outfp)\n",
    "\n",
    "# Clean temp files\n",
    "elevation.clean()"
   ]
  }
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