Coastal Erosion Detection with Sentinel-2 and DeepSeek

// Define the region of interest (North Morocco).
var roi = ee.Geometry.Rectangle([-4.0, 35.0, -3.5, 35.5]);

// Define the date range.
var startDate = '2020-01-01';
var endDate = '2024-01-01';

// Function to mask clouds using the QA60 band.
var maskS2clouds = function(image) {
  var qa = image.select('QA60');
  // Bits 10 and 11 are clouds and cirrus, respectively.
  var cloudBitMask = 1 << 10;
  var cirrusBitMask = 1 << 11;
  // Both flags should be set to zero, indicating clear conditions.
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0).and(
             qa.bitwiseAnd(cirrusBitMask).eq(0));
  return image.updateMask(mask).clip(roi);
};

// Load Sentinel-2 SR data, filter by region and date, and apply cloud masking.
var collection = ee.ImageCollection('COPERNICUS/S2_SR')
    .filterDate(startDate, endDate)
    .filterBounds(roi)
    .map(maskS2clouds);

// Function to calculate NDWI.
var calculateNDWI = function(image) {
  return image.normalizedDifference(['B3', 'B8']).rename('NDWI');
};

// Calculate NDWI for each image in the collection.
var ndwiCollection = collection.map(calculateNDWI);

// Create a median composite of NDWI.
var ndwiMedian = ndwiCollection.median().clip(roi);

// Define visualization parameters.
var ndwiVisParams = {
  min: -1,  
  max: 1,  
  palette: ['blue', 'white', 'green']
};

// Add the NDWI layer to the map.
Map.addLayer(ndwiMedian, ndwiVisParams, 'NDWI Median');
Map.centerObject(roi, 12);

// Export the NDWI median composite to Google Drive.
Export.image.toDrive({
  image: ndwiMedian,
  description: 'NDWI_Median_NorthMorocco',
  folder: 'GEE_Exports',
  scale: 10, // Sentinel-2 resolution
  region: roi,
  maxPixels: 1e13
});