Algorithms/sentinel-1_filtering.ipynb

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        "<table class=\"ee-notebook-buttons\" align=\"left\">\n",
        "    <td><a target=\"_blank\"  href=\"https://github.com/giswqs/earthengine-py-notebooks/tree/master/Algorithms/sentinel-1_filtering.ipynb\"><img width=32px src=\"https://www.tensorflow.org/images/GitHub-Mark-32px.png\" /> View source on GitHub</a></td>\n",
        "    <td><a target=\"_blank\"  href=\"https://nbviewer.jupyter.org/github/giswqs/earthengine-py-notebooks/blob/master/Algorithms/sentinel-1_filtering.ipynb\"><img width=26px src=\"https://upload.wikimedia.org/wikipedia/commons/thumb/3/38/Jupyter_logo.svg/883px-Jupyter_logo.svg.png\" />Notebook Viewer</a></td>\n",
        "    <td><a target=\"_blank\"  href=\"https://colab.research.google.com/github/giswqs/earthengine-py-notebooks/blob/master/Algorithms/sentinel-1_filtering.ipynb\"><img src=\"https://www.tensorflow.org/images/colab_logo_32px.png\" /> Run in Google Colab</a></td>\n",
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        "## Install Earth Engine API and geemap\n",
        "Install the [Earth Engine Python API](https://developers.google.com/earth-engine/python_install) and [geemap](https://geemap.org). The **geemap** Python package is built upon the [ipyleaflet](https://github.com/jupyter-widgets/ipyleaflet) and [folium](https://github.com/python-visualization/folium) packages and implements several methods for interacting with Earth Engine data layers, such as `Map.addLayer()`, `Map.setCenter()`, and `Map.centerObject()`.\n",
        "The following script checks if the geemap package has been installed. If not, it will install geemap, which automatically installs its [dependencies](https://github.com/giswqs/geemap#dependencies), including earthengine-api, folium, and ipyleaflet."
      ]
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "# Installs geemap package\n",
        "import subprocess\n",
        "\n",
        "try:\n",
        "    import geemap\n",
        "except ImportError:\n",
        "    print('Installing geemap ...')\n",
        "    subprocess.check_call([\"python\", '-m', 'pip', 'install', 'geemap'])"
      ],
      "outputs": [],
      "execution_count": null
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "import ee\n",
        "import geemap"
      ],
      "outputs": [],
      "execution_count": null
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "## Create an interactive map \n",
        "The default basemap is `Google Maps`. [Additional basemaps](https://github.com/giswqs/geemap/blob/master/geemap/basemaps.py) can be added using the `Map.add_basemap()` function. "
      ]
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "Map = geemap.Map(center=[40,-100], zoom=4)\n",
        "Map"
      ],
      "outputs": [],
      "execution_count": null
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "## Add Earth Engine Python script "
      ]
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "# Add Earth Engine dataset\n",
        "# Load the Sentinel-1 ImageCollection.\n",
        "sentinel1 = ee.ImageCollection('COPERNICUS/S1_GRD') \\\n",
        "    .filterBounds(ee.Geometry.Point(-122.37383, 37.6193))\n",
        "\n",
        "# Filter by metadata properties.\n",
        "vh = sentinel1 \\\n",
        "  .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VV')) \\\n",
        "  .filter(ee.Filter.listContains('transmitterReceiverPolarisation', 'VH')) \\\n",
        "  .filter(ee.Filter.eq('instrumentMode', 'IW'))\n",
        "\n",
        "# Filter to get images from different look angles.\n",
        "vhAscending = vh.filter(ee.Filter.eq('orbitProperties_pass', 'ASCENDING'))\n",
        "vhDescending = vh.filter(ee.Filter.eq('orbitProperties_pass', 'DESCENDING'))\n",
        "\n",
        "# Create a composite from means at different polarizations and look angles.\n",
        "composite = ee.Image.cat([\n",
        "  vhAscending.select('VH').mean(),\n",
        "  ee.ImageCollection(vhAscending.select('VV').merge(vhDescending.select('VV'))).mean(),\n",
        "  vhDescending.select('VH').mean()\n",
        "]).focal_median()\n",
        "\n",
        "# Display as a composite of polarization and backscattering characteristics.\n",
        "Map.setCenter(-122.37383, 37.6193, 10)\n",
        "Map.addLayer(composite, {'min': [-25, -20, -25], 'max': [0, 10, 0]}, 'composite')\n",
        "\n"
      ],
      "outputs": [],
      "execution_count": null
    },
    {
      "cell_type": "markdown",
      "metadata": {},
      "source": [
        "## Display Earth Engine data layers "
      ]
    },
    {
      "cell_type": "code",
      "metadata": {},
      "source": [
        "Map.addLayerControl() # This line is not needed for ipyleaflet-based Map.\n",
        "Map"
      ],
      "outputs": [],
      "execution_count": null
    }
  ],
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