{ "cells": [ { "cell_type": "markdown", "id": "0", "metadata": {}, "source": [ "\"Open\n", "\n", "Uncomment the following line to install [geemap](https://geemap.org) if needed." ] }, { "cell_type": "code", "execution_count": null, "id": "1", "metadata": {}, "outputs": [], "source": [ "# !pip install geemap" ] }, { "cell_type": "markdown", "id": "2", "metadata": {}, "source": [ "# Using Earth Engine and geemap for mapping surface water dynamics\n", "\n", "**Steps to create Landsat timeseries:**\n", "\n", "1. Pan and zoom to your area of interest (AOI), and click on the map to select a polygon. Alternatively, you can enable `Use user-drawn AOI` and use the Drawing tools (e.g., rectangle) to draw a shape on the map.\n", "2. Adjust the parameters (e.g., band combination, threshold, color, download chart data) if needed. \n", "3. Click the `Submit` button to create timeseries of Landsat imagery and normalized difference indices.\n", "\n", "**Contact:** Dr. Qiusheng Wu ([Website](https://wetlands.io/), [LinkedIn](https://www.linkedin.com/in/qiushengwu), [Twitter](https://twitter.com/giswqs), [YouTube](https://youtube.com/@giswqs))" ] }, { "cell_type": "code", "execution_count": null, "id": "3", "metadata": {}, "outputs": [], "source": [ "# Check geemap installation\n", "import subprocess\n", "\n", "try:\n", " import geemap\n", "except ImportError:\n", " print(\"geemap package is not installed. Installing ...\")\n", " subprocess.check_call([\"python\", \"-m\", \"pip\", \"install\", \"geemap\"])" ] }, { "cell_type": "code", "execution_count": null, "id": "4", "metadata": {}, "outputs": [], "source": [ "# Import libraries\n", "import os\n", "import ee\n", "import geemap\n", "import ipywidgets as widgets\n", "from bqplot import pyplot as plt\n", "from ipyleaflet import WidgetControl" ] }, { "cell_type": "code", "execution_count": null, "id": "5", "metadata": {}, "outputs": [], "source": [ "# Create an interactive map\n", "Map = geemap.Map(center=[40, -100], zoom=4, add_google_map=False)\n", "Map.add_basemap(\"HYBRID\")\n", "Map.add_basemap(\"ROADMAP\")\n", "\n", "# Add Earth Engine data\n", "fc = ee.FeatureCollection(\"TIGER/2018/Counties\")\n", "Map.addLayer(fc, {}, \"US Counties\")\n", "\n", "states = ee.FeatureCollection(\"TIGER/2018/States\")\n", "# Map.addLayer(states, {}, 'US States')\n", "\n", "Map" ] }, { "cell_type": "code", "execution_count": null, "id": "6", "metadata": {}, "outputs": [], "source": [ "# Designe interactive widgets\n", "\n", "style = {\"description_width\": \"initial\"}\n", "\n", "output_widget = widgets.Output(layout={\"border\": \"1px solid black\"})\n", "output_control = WidgetControl(widget=output_widget, position=\"bottomright\")\n", "Map.add_control(output_control)\n", "\n", "admin1_widget = widgets.Text(\n", " description=\"State:\", value=\"Tennessee\", width=200, style=style\n", ")\n", "\n", "admin2_widget = widgets.Text(\n", " description=\"County:\", value=\"Knox\", width=300, style=style\n", ")\n", "\n", "aoi_widget = widgets.Checkbox(\n", " value=False, description=\"Use user-drawn AOI\", style=style\n", ")\n", "\n", "download_widget = widgets.Checkbox(\n", " value=False, description=\"Download chart data\", style=style\n", ")\n", "\n", "\n", "def aoi_change(change):\n", " Map.layers = Map.layers[:4]\n", " Map.user_roi = None\n", " Map.user_rois = None\n", " Map.draw_count = 0\n", " admin1_widget.value = \"\"\n", " admin2_widget.value = \"\"\n", " output_widget.clear_output()\n", "\n", "\n", "aoi_widget.observe(aoi_change, names=\"value\")\n", "\n", "band_combo = widgets.Dropdown(\n", " description=\"Band combo:\",\n", " options=[\n", " \"Red/Green/Blue\",\n", " \"NIR/Red/Green\",\n", " \"SWIR2/SWIR1/NIR\",\n", " \"NIR/SWIR1/Red\",\n", " \"SWIR2/NIR/Red\",\n", " \"SWIR2/SWIR1/Red\",\n", " \"SWIR1/NIR/Blue\",\n", " \"NIR/SWIR1/Blue\",\n", " \"SWIR2/NIR/Green\",\n", " \"SWIR1/NIR/Red\",\n", " ],\n", " value=\"NIR/Red/Green\",\n", " style=style,\n", ")\n", "\n", "year_widget = widgets.IntSlider(\n", " min=1984, max=2020, value=2010, description=\"Selected year:\", width=400, style=style\n", ")\n", "\n", "fmask_widget = widgets.Checkbox(\n", " value=True, description=\"Apply fmask(remove cloud, shadow, snow)\", style=style\n", ")\n", "\n", "\n", "# Normalized Satellite Indices: https://www.usna.edu/Users/oceano/pguth/md_help/html/norm_sat.htm\n", "\n", "nd_options = [\n", " \"Vegetation Index (NDVI)\",\n", " \"Water Index (NDWI)\",\n", " \"Modified Water Index (MNDWI)\",\n", " \"Snow Index (NDSI)\",\n", " \"Soil Index (NDSI)\",\n", " \"Burn Ratio (NBR)\",\n", " \"Customized\",\n", "]\n", "nd_indices = widgets.Dropdown(\n", " options=nd_options,\n", " value=\"Modified Water Index (MNDWI)\",\n", " description=\"Normalized Difference Index:\",\n", " style=style,\n", ")\n", "\n", "first_band = widgets.Dropdown(\n", " description=\"1st band:\",\n", " options=[\"Blue\", \"Green\", \"Red\", \"NIR\", \"SWIR1\", \"SWIR2\"],\n", " value=\"Green\",\n", " style=style,\n", ")\n", "\n", "second_band = widgets.Dropdown(\n", " description=\"2nd band:\",\n", " options=[\"Blue\", \"Green\", \"Red\", \"NIR\", \"SWIR1\", \"SWIR2\"],\n", " value=\"SWIR1\",\n", " style=style,\n", ")\n", "\n", "nd_threshold = widgets.FloatSlider(\n", " value=0,\n", " min=-1,\n", " max=1,\n", " step=0.01,\n", " description=\"Threshold:\",\n", " orientation=\"horizontal\",\n", " style=style,\n", ")\n", "\n", "nd_color = widgets.ColorPicker(\n", " concise=False, description=\"Color:\", value=\"blue\", style=style\n", ")\n", "\n", "\n", "def nd_index_change(change):\n", " if nd_indices.value == \"Vegetation Index (NDVI)\":\n", " first_band.value = \"NIR\"\n", " second_band.value = \"Red\"\n", " elif nd_indices.value == \"Water Index (NDWI)\":\n", " first_band.value = \"NIR\"\n", " second_band.value = \"SWIR1\"\n", " elif nd_indices.value == \"Modified Water Index (MNDWI)\":\n", " first_band.value = \"Green\"\n", " second_band.value = \"SWIR1\"\n", " elif nd_indices.value == \"Snow Index (NDSI)\":\n", " first_band.value = \"Green\"\n", " second_band.value = \"SWIR1\"\n", " elif nd_indices.value == \"Soil Index (NDSI)\":\n", " first_band.value = \"SWIR1\"\n", " second_band.value = \"NIR\"\n", " elif nd_indices.value == \"Burn Ratio (NBR)\":\n", " first_band.value = \"NIR\"\n", " second_band.value = \"SWIR2\"\n", " elif nd_indices.value == \"Customized\":\n", " first_band.value = None\n", " second_band.value = None\n", "\n", "\n", "nd_indices.observe(nd_index_change, names=\"value\")\n", "\n", "submit = widgets.Button(\n", " description=\"Submit\", button_style=\"primary\", tooltip=\"Click me\", style=style\n", ")\n", "\n", "full_widget = widgets.VBox(\n", " [\n", " widgets.HBox([admin1_widget, admin2_widget, aoi_widget, download_widget]),\n", " widgets.HBox([band_combo, year_widget, fmask_widget]),\n", " widgets.HBox([nd_indices, first_band, second_band, nd_threshold, nd_color]),\n", " submit,\n", " ]\n", ")\n", "\n", "full_widget" ] }, { "cell_type": "code", "execution_count": null, "id": "7", "metadata": {}, "outputs": [], "source": [ "# Capture user interaction with the map\n", "\n", "\n", "def handle_interaction(**kwargs):\n", " latlon = kwargs.get(\"coordinates\")\n", " if kwargs.get(\"type\") == \"click\" and not aoi_widget.value:\n", " Map.default_style = {\"cursor\": \"wait\"}\n", " xy = ee.Geometry.Point(latlon[::-1])\n", " selected_fc = fc.filterBounds(xy)\n", "\n", " with output_widget:\n", " output_widget.clear_output()\n", "\n", " try:\n", " feature = selected_fc.first()\n", " admin2_id = feature.get(\"NAME\").getInfo()\n", " statefp = feature.get(\"STATEFP\")\n", " admin1_fc = ee.Feature(\n", " states.filter(ee.Filter.eq(\"STATEFP\", statefp)).first()\n", " )\n", " admin1_id = admin1_fc.get(\"NAME\").getInfo()\n", " admin1_widget.value = admin1_id\n", " admin2_widget.value = admin2_id\n", " Map.layers = Map.layers[:4]\n", " geom = selected_fc.geometry()\n", " layer_name = admin1_id + \"-\" + admin2_id\n", " Map.addLayer(\n", " ee.Image().paint(geom, 0, 2), {\"palette\": \"red\"}, layer_name\n", " )\n", " print(layer_name)\n", " except:\n", " print(\"No feature could be found\")\n", " Map.layers = Map.layers[:4]\n", "\n", " Map.default_style = {\"cursor\": \"pointer\"}\n", " else:\n", " Map.draw_count = 0\n", "\n", "\n", "Map.on_interaction(handle_interaction)" ] }, { "cell_type": "code", "execution_count": null, "id": "8", "metadata": {}, "outputs": [], "source": [ "# Click event handler\n", "\n", "\n", "def submit_clicked(b):\n", " with output_widget:\n", " output_widget.clear_output()\n", " print(\"Computing...\")\n", " Map.default_style = {\"cursor\": \"wait\"}\n", "\n", " try:\n", " admin1_id = admin1_widget.value\n", " admin2_id = admin2_widget.value\n", " band1 = first_band.value\n", " band2 = second_band.value\n", " selected_year = year_widget.value\n", " threshold = nd_threshold.value\n", " bands = band_combo.value.split(\"/\")\n", " apply_fmask = fmask_widget.value\n", " palette = nd_color.value\n", " use_aoi = aoi_widget.value\n", " download = download_widget.value\n", "\n", " if use_aoi:\n", " if Map.user_roi is not None:\n", " roi = Map.user_roi\n", " layer_name = \"User drawn AOI\"\n", " geom = roi\n", " else:\n", " output_widget.clear_output()\n", " print(\"No user AOI could be found.\")\n", " return\n", " else:\n", " statefp = ee.Feature(\n", " states.filter(ee.Filter.eq(\"NAME\", admin1_id)).first()\n", " ).get(\"STATEFP\")\n", " roi = fc.filter(\n", " ee.Filter.And(\n", " ee.Filter.eq(\"NAME\", admin2_id),\n", " ee.Filter.eq(\"STATEFP\", statefp),\n", " )\n", " )\n", " layer_name = admin1_id + \"-\" + admin2_id\n", " geom = roi.geometry()\n", "\n", " Map.layers = Map.layers[:4]\n", " Map.addLayer(ee.Image().paint(geom, 0, 2), {\"palette\": \"red\"}, layer_name)\n", "\n", " images = geemap.landsat_timeseries(\n", " roi=roi,\n", " start_year=1984,\n", " end_year=2020,\n", " start_date=\"01-01\",\n", " end_date=\"12-31\",\n", " apply_fmask=apply_fmask,\n", " )\n", " nd_images = images.map(lambda img: img.normalizedDifference([band1, band2]))\n", " result_images = nd_images.map(lambda img: img.gt(threshold))\n", "\n", " selected_image = ee.Image(\n", " images.toList(images.size()).get(selected_year - 1984)\n", " )\n", " selected_result_image = ee.Image(\n", " result_images.toList(result_images.size()).get(selected_year - 1984)\n", " ).selfMask()\n", "\n", " vis_params = {\"bands\": bands, \"min\": 0, \"max\": 3000}\n", "\n", " Map.addLayer(selected_image, vis_params, \"Landsat \" + str(selected_year))\n", " Map.addLayer(\n", " selected_result_image,\n", " {\"palette\": palette},\n", " \"Result \" + str(selected_year),\n", " )\n", "\n", " def cal_area(img):\n", " pixel_area = img.multiply(ee.Image.pixelArea()).divide(1e4)\n", " img_area = pixel_area.reduceRegion(\n", " **{\n", " \"geometry\": geom,\n", " \"reducer\": ee.Reducer.sum(),\n", " \"scale\": 1000,\n", " \"maxPixels\": 1e12,\n", " \"bestEffort\": True,\n", " }\n", " )\n", " return img.set({\"area\": img_area})\n", "\n", " areas = result_images.map(cal_area)\n", " stats = areas.aggregate_array(\"area\").getInfo()\n", " x = list(range(1984, 2021))\n", " y = [item.get(\"nd\") for item in stats]\n", "\n", " fig = plt.figure(1)\n", " fig.layout.height = \"270px\"\n", " plt.clear()\n", " plt.plot(x, y)\n", " plt.title(\"Temporal trend (1984-2020)\")\n", " plt.xlabel(\"Year\")\n", " plt.ylabel(\"Area (ha)\")\n", "\n", " output_widget.clear_output()\n", "\n", " plt.show()\n", "\n", " if download:\n", " out_dir = os.path.join(os.path.expanduser(\"~\"), \"Downloads\")\n", " out_name = \"chart_\" + geemap.random_string() + \".csv\"\n", " out_csv = os.path.join(out_dir, out_name)\n", " if not os.path.exists(out_dir):\n", " os.makedirs(out_dir)\n", " with open(out_csv, \"w\") as f:\n", " f.write(\"year, area (ha)\\n\")\n", " for index, item in enumerate(x):\n", " line = \"{},{:.2f}\\n\".format(item, y[index])\n", " f.write(line)\n", " link = geemap.create_download_link(\n", " out_csv, title=\"Click here to download the chart data: \"\n", " )\n", " display(link)\n", "\n", " except Exception as e:\n", " print(e)\n", " print(\"An error occurred during computation.\")\n", "\n", " Map.default_style = {\"cursor\": \"default\"}\n", "\n", "\n", "submit.on_click(submit_clicked)" ] } ], "metadata": { "kernelspec": { "display_name": "Python 3", "language": "python", "name": "python3" } }, "nbformat": 4, "nbformat_minor": 5 }