notebooks/unit05/unit05_05.ipynb

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  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "This notebook was prepared by Cayetano Benavent, 2016."
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "# Reading a raster with GDAL"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 26,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "from osgeo import gdal"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 27,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "input_filename = \"../../data/mde/h10_1050_2-2/h10_1050_2-2.tif\""
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 28,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "src_ds = gdal.Open(input_filename)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 29,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "PROJCS[\"ETRS89 / UTM zone 30N (N-E)\",GEOGCS[\"ETRS89\",DATUM[\"European_Terrestrial_Reference_System_1989\",SPHEROID[\"GRS 1980\",6378137,298.2572221010002,AUTHORITY[\"EPSG\",\"7019\"]],AUTHORITY[\"EPSG\",\"6258\"]],PRIMEM[\"Greenwich\",0],UNIT[\"degree\",0.0174532925199433],AUTHORITY[\"EPSG\",\"4258\"]],PROJECTION[\"Transverse_Mercator\"],PARAMETER[\"latitude_of_origin\",0],PARAMETER[\"central_meridian\",-3],PARAMETER[\"scale_factor\",0.9996],PARAMETER[\"false_easting\",500000],PARAMETER[\"false_northing\",0],UNIT[\"metre\",1,AUTHORITY[\"EPSG\",\"9001\"]],AUTHORITY[\"EPSG\",\"3042\"]]\n"
     ]
    }
   ],
   "source": [
    "src_crs = src_ds.GetProjection()\n",
    "print(src_crs)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 30,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "(282285.0, 10.0, 0.0, 4074645.0, 0.0, -10.0)\n"
     ]
    }
   ],
   "source": [
    "src_geot = src_ds.GetGeoTransform()\n",
    "print(src_geot)"
   ]
  },
  {
   "cell_type": "markdown",
   "metadata": {},
   "source": [
    "GDAL Geotransform (affine transformation coefficients):\n",
    "- GeoTransform[0] - top left x\n",
    "- GeoTransform[1] - x scale\n",
    "- GeoTransform[2] - rotation (shear in x direction)\n",
    "- GeoTransform[3] - top left y\n",
    "- GeoTransform[4] - rotation (shear in y direction)\n",
    "- GeoTransform[5] - y scale (negative value)\n",
    "\n",
    "The affine transform coefficients map pixel coordinates into georeferenced space.\n",
    "\n",
    "More info: http://www.gdal.org/gdal_datamodel.html\n"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 31,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "1\n"
     ]
    }
   ],
   "source": [
    "count_bands = src_ds.RasterCount\n",
    "print(count_bands)"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 32,
   "metadata": {
    "collapsed": false
   },
   "outputs": [
    {
     "name": "stdout",
     "output_type": "stream",
     "text": [
      "Minimum=557.4820, Maximum=1,641.9017, Mean=1,009.9320, StdDev=206.4086\n"
     ]
    }
   ],
   "source": [
    "for band in range(count_bands):\n",
    "    src_band = src_ds.GetRasterBand(band + 1)\n",
    "    stats = src_band.GetStatistics(True, True)\n",
    "    if stats:\n",
    "        print(\"Minimum={:,.4f}, Maximum={:,.4f}, Mean={:,.4f}, StdDev={:,.4f}\".format(stats[0], stats[1], stats[2], stats[3]))"
   ]
  },
  {
   "cell_type": "code",
   "execution_count": 33,
   "metadata": {
    "collapsed": true
   },
   "outputs": [],
   "source": [
    "src_ds = None"
   ]
  }
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