Update app.py

app.py

@@ -95,7 +95,7 @@ def reduce_zonal_ndvi(image, ee_object):
 
 def calculate_NDVI(image):
     ndvi = image.normalizedDifference(['B8', 'B4']).rename('NDVI')
-    return image.addBands(ndvi)
+    return ndvi
 
 # Get Zonal NDVI
 def get_zonal_ndvi(collection, geom_ee_object):
@@ -107,9 +107,9 @@ def get_zonal_ndvi(collection, geom_ee_object):
   return df
 
 def get_zonal_ndviYoY(collection, geom_ee_object):
-    collection = collection.map(lambda image: calculate_NDVI)
-    max_ndvi = collection.select('NDVI').max()
-    reduced_max_ndvi = image.reduceRegion(
+    ndvi_collection = collection.map(lambda image: calculate_NDVI)
+    max_ndvi = ndvi_collection.max()
+    reduced_max_ndvi = max_ndvi.reduceRegion(
         reducer=ee.Reducer.mean(),
         geometry=ee_object.geometry(),
         scale=10,