Calculate Landsat surface reflectance Tasseled Cap transformation using Earth Engine

gee_calculate_tc.ipynb

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  "metadata": {
    "colab": {
      "name": "gee_calculate_tc.ipynb",
      "provenance": [],
      "authorship_tag": "ABX9TyOy8ZPfcgLrl76IXmNACMAi",
      "include_colab_link": true
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    "kernelspec": {
      "name": "python3",
      "display_name": "Python 3"
    },
    "language_info": {
      "name": "python"
    }
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  "cells": [
    {
      "cell_type": "markdown",
      "metadata": {
        "id": "view-in-github",
        "colab_type": "text"
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      "source": [
        "<a href=\"https://colab.research.google.com/gist/jdbcode/afdf3cd3381f1987bcbeaa718607518c/gee_calculate_tc.ipynb\" target=\"_parent\"><img src=\"https://colab.research.google.com/assets/colab-badge.svg\" alt=\"Open In Colab\"/></a>"
      ]
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "sLHNETPr-0-w"
      },
      "source": [
        "import ee\n",
        "ee.Authenticate()\n",
        "ee.Initialize()"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "9POJ8TQYCEiJ"
      },
      "source": [
        "import folium\n",
        "import pprint\n",
        "\n",
        "def add_ee_layer(self, ee_image_object, vis_params, name):\n",
        "  map_id_dict = ee.Image(ee_image_object).getMapId(vis_params)\n",
        "  folium.raster_layers.TileLayer(\n",
        "      tiles=map_id_dict['tile_fetcher'].url_format,\n",
        "      attr='Map Data &copy; <a href=\"https://earthengine.google.com/\">Google Earth Engine</a>',\n",
        "      name=name,\n",
        "      overlay=True,\n",
        "      control=True\n",
        "  ).add_to(self)\n",
        "\n",
        "folium.Map.add_ee_layer = add_ee_layer"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "yLUAdtWw-5BZ"
      },
      "source": [
        "# For Landsat surface reflectance (see: Crist (1985) and Huang et al. (2002)).\n",
        "# Note that band selection is for Landsat 8.\n",
        "def calc_tc(img):\n",
        "    b = ee.Image(img).select(['B2', 'B3', 'B4', 'B5', 'B6', 'B7'])\n",
        "    brt_coeffs = ee.Image.constant([0.2043, 0.4158, 0.5524, 0.5741, 0.3124, 0.2303])\n",
        "    grn_coeffs = ee.Image.constant([-0.1603, -0.2819, -0.4934, 0.7940, -0.0002, -0.1446])\n",
        "    wet_coeffs = ee.Image.constant([0.0315, 0.2021, 0.3102, 0.1594, -0.6806, -0.6109])\n",
        "\n",
        "    brightness = b.multiply(brt_coeffs).reduce(ee.Reducer.sum())\n",
        "    greenness = b.multiply(grn_coeffs).reduce(ee.Reducer.sum())\n",
        "    wetness = b.multiply(wet_coeffs).reduce(ee.Reducer.sum())\n",
        "    return ee.Image.cat(brightness, greenness, wetness).rename(['tcb', 'tcg', 'tcw'])"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "uXETYXvoAnGW"
      },
      "source": [
        "col = (ee.ImageCollection('LANDSAT/LC08/C01/T1_SR')\n",
        "       .filterBounds(ee.Geometry.Point([-123.2654, 44.5662]))\n",
        "       .filterDate('2020-06-01', '2020-08-01'))\n",
        "\n",
        "tc_col = col.map(calc_tc)"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "6ZCqafy6CNMu"
      },
      "source": [
        "tc_img = tc_col.first()\n",
        "pprint.pprint(tc_img.getInfo())"
      ],
      "execution_count": null,
      "outputs": []
    },
    {
      "cell_type": "code",
      "metadata": {
        "id": "ii2w-npXFGz_"
      },
      "source": [
        "tc_params = {\n",
        "    'bands': ['tcb', 'tcg', 'tcw'],\n",
        "    'min': [604, -49, -2245],\n",
        "    'max': [5592, 3147, 843],\n",
        "}\n",
        "map = folium.Map(location=[44.5662, -123.2654], zoom_start=9)\n",
        "map.add_ee_layer(col.first(), {'bands': ['B6', 'B5', 'B4'], 'min': 100, 'max': 4000}, 'B6, B5, B4')\n",
        "map.add_ee_layer(tc_col.first(), tc_params, 'TC')\n",
        "display(map.add_child(folium.LayerControl()))"
      ],
      "execution_count": null,
      "outputs": []
    }
  ]
}