update app.py

app.py

@@ -242,10 +242,42 @@ def aggregate_data_yearly(collection):
     yearly_images = ee.List(grouped_by_year.map(calculate_yearly_mean))
     return ee.ImageCollection(yearly_images)
 
+# Define the function before using it
+def calculate_cloud_percentage(image, cloud_band='QA60'):
+    """
+    Calculate the percentage of cloud-covered pixels in an image using the QA60 bitmask.
+    Assumes the presence of the QA60 cloud mask band.
+    """
+    # Decode the QA60 bitmask
+    qa60 = image.select(cloud_band)
+    opaque_clouds = qa60.bitwiseAnd(1 << 10)  # Bit 10: Opaque clouds
+    cirrus_clouds = qa60.bitwiseAnd(1 << 11)  # Bit 11: Cirrus clouds
+    # Combine both cloud types into a single cloud mask
+    cloud_mask = opaque_clouds.Or(cirrus_clouds)
+    # Count total pixels and cloudy pixels
+    total_pixels = qa60.reduceRegion(
+        reducer=ee.Reducer.count(),
+        geometry=image.geometry(),
+        scale=60,  # QA60 resolution is 60 meters
+        maxPixels=1e13
+    ).get(cloud_band)
+    cloudy_pixels = cloud_mask.reduceRegion(
+        reducer=ee.Reducer.sum(),
+        geometry=image.geometry(),
+        scale=60,  # QA60 resolution is 60 meters
+        maxPixels=1e13
+    ).get(cloud_band)
+    # Calculate cloud percentage
+    if total_pixels == 0:
+        return 0  # Avoid division by zero
+    return ee.Number(cloudy_pixels).divide(ee.Number(total_pixels)).multiply(100)
+
+# Use the function in preprocessing
 def preprocess_collection(collection, tile_cloud_threshold, pixel_cloud_threshold):
     def filter_tile(image):
         cloud_percentage = calculate_cloud_percentage(image, cloud_band='QA60')
         return image.set('cloud_percentage', cloud_percentage).updateMask(cloud_percentage.lt(tile_cloud_threshold))
+    
     def mask_cloudy_pixels(image):
         qa60 = image.select('QA60')
         opaque_clouds = qa60.bitwiseAnd(1 << 10)
@@ -253,6 +285,7 @@ def preprocess_collection(collection, tile_cloud_threshold, pixel_cloud_threshol
         cloud_mask = opaque_clouds.Or(cirrus_clouds)
         clear_pixels = cloud_mask.Not()
         return image.updateMask(clear_pixels)
+    
     filtered_collection = collection.map(filter_tile)
     masked_collection = filtered_collection.map(mask_cloudy_pixels)
     return masked_collection