update app.py

app.py

@@ -26,96 +26,81 @@ with open(os.path.expanduser("~/.config/earthengine/credentials"), "w") as f:
 
 ee.Initialize(project='ee-yashsacisro24')
 
-# Load JSON data for Sentinel dataset options
+# Load Sentinel dataset options from JSON file
 with open("sentinel_datasets.json") as f:
     data = json.load(f)
 
-# Define index calculation functions
-def calculate_ndvi(image):
-    """Calculate NDVI."""
-    return image.normalizedDifference(['B5', 'B4']).rename('NDVI')
-
-def calculate_ndwi(image):
-    """Calculate NDWI."""
-    return image.normalizedDifference(['B3', 'B5']).rename('NDWI')
-
-def calculate_avg_no2(image):
-    """Calculate average NO2."""
-    return image.select('NO2').reduceRegion(
-        reducer=ee.Reducer.mean(),
-        geometry=image.geometry(),
-        scale=1000
-    ).get('NO2')
-
-def calculate_custom_formula(image, formula):
-    """Apply a custom formula to the image."""
-    return image.expression(formula).rename('Custom Index')
-
-# Streamlit UI - Title
-st.title("Sentinel Dataset Selector and Earth Engine Index Calculator")
-
-# Sentinel Dataset Selector Section
-st.header("Sentinel Dataset Selector")
+# Display title and dataset selection
+st.title("Sentinel Dataset and Index Calculator")
 
 # Step 1: Select main dataset category
 main_selection = st.selectbox("Select Sentinel Dataset Category", list(data.keys()))
 
 # Step 2: Display sub-options based on main selection
-sub_selection = None
 if main_selection:
     sub_options = data[main_selection]["sub_options"]
     sub_selection = st.selectbox("Select Specific Dataset ID", list(sub_options.keys()))
 
-#     # Step 3: Display band selection based on sub-selection with max 3 selections
-#     selected_bands = []
-#     if sub_selection:
-#         bands = sub_options[sub_selection]
-#         st.write("Select up to 3 bands:")
-        
-#         # Display bands in a side-by-side layout with three columns
-#         cols = st.columns(3)
-#         for i, band in enumerate(bands):
-#             with cols[i % 3]:
-#                 if st.checkbox(band, key=band):
-#                     selected_bands.append(band)
-#                 # Limit selection to a maximum of 3 bands
-#                 if len(selected_bands) == 3:
-#                     break
-
-#         # Show selected bands
-#         st.write("Selected Bands:", selected_bands)
 
 # Earth Engine Index Calculator Section
 st.header("Earth Engine Index Calculator")
 
-# Step 4: Select Index Calculation Option
+# Step 4: Choose Index or Custom Formula
 index_choice = st.selectbox("Select an Index or Enter Custom Formula", ['NDVI', 'NDWI', 'Average NO₂', 'Custom Formula'])
 
-# Step 5: Custom Formula Input
+# Step 5: Enter Custom Formula if selected
 custom_formula = ""
 if index_choice == 'Custom Formula':
     custom_formula = st.text_input("Enter Custom Formula (e.g., 'B5 - B4 / B5 + B4')")
 
-# Step 6: Calculate and Display Results based on selected index or formula
-if sub_selection and st.button("Calculate Index"):
-    # Use the selected dataset from the main and sub-selection as an ImageCollection
-    collection = ee.ImageCollection(data[main_selection]["sub_options"][sub_selection]).filterDate('2020-01-01', '2020-1-31')
-    image = collection.first()  # Using the first image in the collection as an example
-
-    result_image = None
-    if index_choice == 'NDVI':
-        result_image = calculate_ndvi(image)
-    elif index_choice == 'NDWI':
-        result_image = calculate_ndwi(image)
-    elif index_choice == 'Average NO₂':
-        result = calculate_avg_no2(image)
-        st.write("Average NO₂ Concentration:", result.getInfo())
-    elif index_choice == 'Custom Formula' and custom_formula:
-        result_image = calculate_custom_formula(image, custom_formula)
-
-    # If an index image is generated, add it to the map
-    if result_image:
-        Map = geemap.Map()
-        Map.centerObject(image, 10)
-        Map.addLayer(result_image, {}, index_choice)
-        Map.to_streamlit(height=600)
+# Define functions for index calculations
+def calculate_ndvi(image):
+    return image.normalizedDifference(['B5', 'B4']).rename('NDVI')
+
+def calculate_ndwi(image):
+    return image.normalizedDifference(['B3', 'B5']).rename('NDWI')
+
+def calculate_avg_no2(image):
+    return image.select('NO2').reduceRegion(
+        reducer=ee.Reducer.mean(),
+        geometry=image.geometry(),
+        scale=1000
+    ).get('NO2')
+
+def calculate_custom_formula(image, formula):
+    return image.expression(formula).rename('Custom Index')
+
+# Step 6: Perform the calculation based on user choice
+result_image = None
+if st.button("Calculate Index"):
+    try:
+        # Load dataset based on user selection
+        dataset_id = sub_selection  # Dataset ID from the JSON structure
+        collection = ee.ImageCollection(dataset_id).filterDate('2020-01-01', '2020-12-31')
+        image = collection.first()  # Using the first image in the collection as an example
+
+        # Choose calculation based on user selection
+        if index_choice == 'NDVI':
+            result_image = calculate_ndvi(image)
+        elif index_choice == 'NDWI':
+            result_image = calculate_ndwi(image)
+        elif index_choice == 'Average NO₂':
+            result = calculate_avg_no2(image)
+            st.write("Average NO₂ Concentration:", result.getInfo())
+        elif index_choice == 'Custom Formula' and custom_formula:
+            result_image = calculate_custom_formula(image, custom_formula)
+
+        # Visualization Parameters for Index Layers
+        vis_params = {"min": 0, "max": 1, "palette": ["blue", "white", "green"]}
+
+        # If an index image is generated, add it to the map
+        if result_image:
+            Map = geemap.Map()
+            Map.setCenter(-100.0, 40.0, 4)  # Example coordinates; adjust as needed
+            Map.addLayer(result_image, vis_params, index_choice)
+            Map.to_streamlit(height=600)
+        else:
+            st.warning("Result image not generated; check parameters.")
+    
+    except ee.EEException as e:
+        st.error(f"Earth Engine Error: {e}")