Update app.py

app.py

@@ -113,16 +113,27 @@ def get_dem_slope_maps(buffer_ee_geometry):
     # Create the map for DEM
     dem_map = gee_folium.Map()
     dem_layer = ee.Image("USGS/SRTMGL1_003").clip(buffer_ee_geometry)  
-    vis_params = {"min": 0, "max": 300, "palette": ["blue", "green", "yellow", "red"]}
-    dem_map.addLayer(dem_layer, vis_params, "DEM Layer")
+    
+    # Generate contour lines using elevation thresholds
+    contour_interval = 10
+    contours = terrain.select('elevation').subtract(terrain.select('elevation').mod(contour_interval)).rename('contours')
+
+    # Calculate the minimum and maximum values
+    stats = dem_layer.reduceRegion(reducer=ee.Reducer.minMax(),scale=30,maxPixels=1e13)
+    
+    # Print the results
+    max_value = stats.get('contours_max').getInfo()
+
+    vis_params = {"min": 0, "max": max_value, "palette": ["blue", "green", "yellow", "red"]}
+    dem_map.addLayer(contours, vis_params, "Contours")
     # Create a colormap
     colormap = cm.LinearColormap(colors=vis_params['palette'], vmin=vis_params['min'], vmax=vis_params['max'])
     dem_map.add_child(colormap)
-    dem_map.addLayer(buffer_ee_geometry, )
     
     # Create the map for Slope
     slope_map = gee_folium.Map()
-    slope_layer = ee.Terrain.slope(dem_layer)  # Calculate slope from the DEM
+    # Calculate slope from the DEM
+    slope_layer = ee.Terrain.slope(ee.Image("USGS/SRTMGL1_003")).clip(buffer_ee_geometry)  
     vis_params = {"min": 0, "max": 20, "palette": ["blue", "green", "yellow", "red"]}
     slope_map.addLayer(slope_layer, vis_params, "Slope Layer")
     # Create a colormap
@@ -467,14 +478,9 @@ if "result" in st.session_state:
             m.to_streamlit()
 
     st.write("<h3><div style='text-align: center;'>DEM and Slope from SRTM at 30m resolution</div></h3>", unsafe_allow_html=True)
-    dem_col, slope_col = st.columns(2)
+    cols = st.columns(2)
     dem_map, slope_map = get_dem_slope_maps(ee.Geometry(buffer_geometry_gdf.to_crs(4326).geometry.item().__geo_interface__))
-    # DEM Map
-    dem_col.write("DEM Map")
-    add_geometry_to_maps([dem_map])
-    dem_map.to_streamlit()
-    
-    # Slope Map
-    slope_col.write("Slope Map")
-    slope_map.to_streamlit()
-    add_geometry_to_maps([slope_map])
+    for col, param_map in zip(cols, [dem_map, slope_map]):
+        with col:
+            add_geometry_to_maps([param_map])
+            param_map.to_streamlit()