Enable GEE API and create web UI

Log into Google Cloud Console

Select the project and “IAM & Admin” tab

Create service account

Create new key (JSON) and save in your local computer

Check the account is added

Install necessary packages

  pip install earthengine-api streamlit folium streamlit-folium

  import ee
  import streamlit as st
  import datetime
  import os

  # Initialize GEE authentication and setup
  service_account = 'orbtrace@forest-in-rochester-hills.iam.gserviceaccount.com'
  script_dir = os.path.dirname(os.path.abspath(__file__))
  key_path = os.path.join(script_dir, '../../GoogleCloudKeys/forest-in-rochester-hills-084f70827372.json') 
  credentials = ee.ServiceAccountCredentials(service_account, key_path)
  ee.Initialize(credentials)

  st.title("Yearly Satellite Image NDVI Viewer")

  # Year selection UI slider
  year = st.slider("Select the year", 2015, datetime.datetime.now().year, 2020)

  # Set date range based on selected year
  start_date = f'{year}-01-01'
  end_date = f'{year}-12-31'

  # Retrieve Sentinel-2 image collection from GEE filtered by date, location, and cloud cover
  collection = (ee.ImageCollection('COPERNICUS/S2_SR')
                .filterDate(start_date, end_date)
                .filterBounds(ee.Geometry.Point(-83.141, 42.658))  # Example coordinate for Rochester Hills
                .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 20)))

  # Compute median image from collection
  image = collection.median()

  # Calculate NDVI using NIR (B8) and Red (B4) bands
  ndvi = image.normalizedDifference(['B8', 'B4']).rename('NDVI')

  # Visualization parameters for NDVI image
  ndvi_params = {
      'min': 0.0,
      'max': 1.0,
      'palette': ['white', 'green']
  }

  # Convert NDVI image to a tile map URL
  map_id_dict = ndvi.getMapId(ndvi_params)
  tile_url = map_id_dict['tile_fetcher'].url_format

  st.write(f"Selected year: {year}")

  # Import folium and streamlit_folium for displaying tile map on Streamlit (optional)
  import folium
  from streamlit_folium import st_folium

  # Create map centered at Rochester Hills coordinates
  m = folium.Map(location=[42.658, -83.141], zoom_start=11)
  folium.TileLayer(
      tiles=tile_url,
      attr='Google Earth Engine',
      name='NDVI',
      overlay=True,
      control=True
  ).add_to(m)

  # Display the map on Streamlit app
  st_folium(m, width=700, height=500)

Go to the file directory and run the code

  streamlit run app.py