Hướng dẫn đọc file .nc

opencdf.ipynb

{
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   "source": [
    "### Hướng dẫn cách đọc opencdf file bằng python\n",
    "\n",
    "1. Cài conda, tạo môi trường tên pydata: `conda create -n pydata`, kích hoạt môi trường pydata: `source activate pydata`\n",
    "2. Cài python 3.5 và các thư viện cần thiết:\n",
    "```sh\n",
    "conda install python=3.5 jupyter xarray netcdf4\n",
    "conda install -c conda-forge netcdftime --no-deps\n",
    "```\n",
    "3. Download 1 số file mẫu từ trang https://www.unidata.ucar.edu/software/netcdf/examples/files.html\n",
    "4. Chạy `jupyter notebook` và download file notebook ví dụ này: https://gist.github.com/fehiepsi/08471b6f63c9eaef3c762f30dc263088\n",
    "5. Tham khảo thêm cách sử dụng xarray ở: http://xarray.pydata.org/en/stable/"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 1,
   "metadata": {},
   "outputs": [],
   "source": [
    "import xarray"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 2,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<xarray.Dataset>\n",
       "Dimensions:    (bnds: 2, lat: 128, lon: 256, plev: 17, time: 1)\n",
       "Coordinates:\n",
       "  * lat        (lat) float32 -88.927734 -87.538704 -86.14147 -84.742386 ...\n",
       "  * lon        (lon) float32 0.0 1.40625 2.8125 4.21875 5.625 7.03125 8.4375 ...\n",
       "  * plev       (plev) float64 1e+05 9.25e+04 8.5e+04 7e+04 6e+04 5e+04 4e+04 ...\n",
       "  * time       (time) datetime64[ns] 2000-05-16T12:00:00\n",
       "Dimensions without coordinates: bnds\n",
       "Data variables:\n",
       "    area       (lat, lon) float32 ...\n",
       "    lat_bnds   (lat, bnds) float64 ...\n",
       "    lon_bnds   (lon, bnds) float64 ...\n",
       "    msk_rgn    (lat, lon) int32 ...\n",
       "    pr         (time, lat, lon) float32 ...\n",
       "    tas        (time, lat, lon) float32 ...\n",
       "    time_bnds  (time, bnds) float64 ...\n",
       "    ua         (time, plev, lat, lon) float32 ...\n",
       "Attributes:\n",
       "    CVS_Id:              $Id$\n",
       "    creation_date:       \n",
       "    prg_ID:              Source file unknown Version unknown Date unknown\n",
       "    cmd_ln:              bds -x 256 -y 128 -m 23 -o /data/zender/data/dst_T85.nc\n",
       "    history:             Tue Oct 25 15:08:51 2005: ncks -O -x -v va -m sresa1...\n",
       "    table_id:            Table A1\n",
       "    title:               model output prepared for IPCC AR4\n",
       "    institution:         NCAR (National Center for Atmospheric \\nResearch, Bo...\n",
       "    source:              CCSM3.0, version beta19 (2004): \\natmosphere: CAM3.0...\n",
       "    contact:             [email protected]\n",
       "    project_id:          IPCC Fourth Assessment\n",
       "    Conventions:         CF-1.0\n",
       "    references:          Collins, W.D., et al., 2005:\\n The Community Climate...\n",
       "    acknowledgment:       Any use of CCSM data should acknowledge the contrib...\n",
       "    realization:         1\n",
       "    experiment_id:       720 ppm stabilization experiment (SRESA1B)\n",
       "    comment:             This simulation was initiated from year 2000 of \\n C...\n",
       "    model_name_english:  NCAR CCSM"
      ]
     },
     "execution_count": 2,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "ds = xarray.open_dataset(\"sresa1b_ncar_ccsm3-example.nc\")\n",
    "ds"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 3,
   "metadata": {},
   "outputs": [
    {
     "data": {
      "text/plain": [
       "<xarray.Dataset>\n",
       "Dimensions:    (bnds: 2, lat: 170, lon: 180, time: 24)\n",
       "Coordinates:\n",
       "  * lon        (lon) float64 1.0 3.0 5.0 7.0 9.0 11.0 13.0 15.0 17.0 19.0 ...\n",
       "  * lat        (lat) float64 -79.5 -78.5 -77.5 -76.5 -75.5 -74.5 -73.5 -72.5 ...\n",
       "  * time       (time) datetime64[ns] 2001-01-16 2001-02-16 2001-03-16 ...\n",
       "Dimensions without coordinates: bnds\n",
       "Data variables:\n",
       "    lon_bnds   (lon, bnds) float64 ...\n",
       "    lat_bnds   (lat, bnds) float64 ...\n",
       "    time_bnds  (time, bnds) float64 ...\n",
       "    tos        (time, lat, lon) float32 ...\n",
       "Attributes:\n",
       "    title:          IPSL  model output prepared for IPCC Fourth Assessment SR...\n",
       "    institution:    IPSL (Institut Pierre Simon Laplace, Paris, France)\n",
       "    source:         IPSL-CM4_v1 (2003) : atmosphere : LMDZ (IPSL-CM4_IPCC, 96...\n",
       "    contact:        Sebastien Denvil, [email protected]\n",
       "    project_id:     IPCC Fourth Assessment\n",
       "    table_id:       Table O1 (13 November 2004)\n",
       "    experiment_id:  SRES A2 experiment\n",
       "    realization:    1\n",
       "    cmor_version:   0.96\n",
       "    Conventions:    CF-1.0\n",
       "    history:        YYYY/MM/JJ: data generated; YYYY/MM/JJ+1 data transformed...\n",
       "    references:     Dufresne et al, Journal of Climate, 2015, vol XX, p 136\n",
       "    comment:        Test drive"
      ]
     },
     "execution_count": 3,
     "metadata": {},
     "output_type": "execute_result"
    }
   ],
   "source": [
    "ds2 = xarray.open_dataset(\"tos_O1_2001-2002.nc\")\n",
    "ds2"
   ]
  }
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