Crop Stress Detection with Sentinel-2 Red Edge and DeepSeek

// Define the study area (North Morocco).
var roi = ee.Geometry.Polygon([[[-5.5, 32], [-3, 32], [-3, 35], [-5.5, 35]]]);

// Define the date range.
var startDate = '2023-06-01';
var endDate = '2023-08-31';

// Import Sentinel-2 SR data.
var s2 = ee.ImageCollection('COPERNICUS/S2_SR')
    .filterBounds(roi)
    .filterDate(startDate, endDate)
    .filter(ee.Filter.lt('CLOUDY_PIXEL_PERCENTAGE', 20));

// Function to mask clouds using the QA60 band.
function maskS2clouds(image) {
  var qa = image.select('QA60');
  var cloudBitMask = 1 << 10;
  var cirrusBitMask = 1 << 11;
  var mask = qa.bitwiseAnd(cloudBitMask).eq(0)
      .and(qa.bitwiseAnd(cirrusBitMask).eq(0));
  return image.updateMask(mask).divide(10000); // Scale to 0-1
}

// Apply cloud masking and calculate NDRE.
var s2_masked = s2.map(maskS2clouds);

var ndre = s2_masked.map(function(image) {
  return image.normalizedDifference(['B8A', 'B5']).rename('NDRE');
});

// Composite the NDRE images.
var ndre_composite = ndre.median();

// Define a threshold for crop stress (NDRE < 0.2).
var stress_threshold = 0.2;

// Create a binary mask for stressed areas.
var stressed_mask = ndre_composite.lt(stress_threshold);

// Visualize the results.
Map.centerObject(roi, 10);
Map.addLayer(ndre_composite, {min: 0, max: 0.7, palette: ['red', 'yellow', 'green']}, 'NDRE Composite');
Map.addLayer(stressed_mask.updateMask(stressed_mask), {palette: 'red'}, 'Stressed Areas');

// Export the stressed area mask to Google Drive.
Export.image.toDrive({
  image: stressed_mask,
  description: 'crop_stress_mask',
  folder: 'GEE_Exports',
  region: roi,
  scale: 10,
  maxPixels: 1e13
});