Update app.py

app.py

@@ -205,57 +205,59 @@ def get_wayback_data():
         print(f"Could not fetch or parse Wayback data: {e}")
         return pd.DataFrame() # Return empty dataframe on failure
 
-def get_dem_slope_maps(ee_geometry, wayback_url=None, wayback_title=None):
+def get_dem_slope_maps(ee_geometry, map_center, zoom=12, wayback_url=None, wayback_title=None):
     """Creates DEM and Slope maps from SRTM data, using wayback tiles as a basemap if available."""
     one_time_setup()
 
     # --- DEM Map ---
-    dem_map = gee_folium.Map(center_object=ee_geometry, zoom_start=12)
+    dem_map = gee_folium.Map(location=map_center, zoom_start=zoom)
     if wayback_url:
         dem_map.add_tile_layer(wayback_url, name=wayback_title, attribution="Esri")
     else:
         dem_map.add_basemap("SATELLITE")
 
+    dem_map_html = "<div>No DEM data available for this area.</div>"
     try:
         dem_layer = ee.Image("USGS/SRTMGL1_003").resample("bilinear").reproject(crs="EPSG:4326", scale=30).clip(ee_geometry)
         stats = dem_layer.reduceRegion(reducer=ee.Reducer.minMax(), geometry=ee_geometry, scale=30, maxPixels=1e9).getInfo()
         
         if stats and stats.get('elevation_min') is not None:
             min_val, max_val = stats['elevation_min'], stats['elevation_max']
-            vis_params = {"min": min_val, "max": max_val, "palette": ['#0000FF', '#00FF00', '#FFFF00', '#FF0000']} # Blue to Red
+            vis_params = {"min": min_val, "max": max_val, "palette": ['#0000FF', '#00FF00', '#FFFF00', '#FF0000']}
             dem_map.addLayer(dem_layer, vis_params, "Elevation")
             dem_map.add_colorbar(vis_params=vis_params, label="Elevation (m)")
-        else:
-            dem_map_html = "<div>No DEM data available for this area.</div>"
+        
+        dem_map.addLayerControl()
+        dem_map_html = dem_map._repr_html_()
+
     except Exception as e:
         print(f"Error creating DEM map: {e}")
         dem_map_html = f"<div>Error creating DEM map: {e}</div>"
 
-    dem_map.addLayerControl()
-    dem_map_html = dem_map._repr_html_()
 
     # --- Slope Map ---
-    slope_map = gee_folium.Map(center_object=ee_geometry, zoom_start=12)
+    slope_map = gee_folium.Map(location=map_center, zoom_start=zoom)
     if wayback_url:
         slope_map.add_tile_layer(wayback_url, name=wayback_title, attribution="Esri")
     else:
         slope_map.add_basemap("SATELLITE")
 
+    slope_map_html = "<div>No Slope data available for this area.</div>"
     try:
         slope_layer = ee.Terrain.slope(dem_layer)
-        slope_vis_params = {"min": 0, "max": 60, "palette": ['#00FF00', '#FFFF00', '#FFA500', '#FF0000']} # Green to Red
+        slope_vis_params = {"min": 0, "max": 60, "palette": ['#00FF00', '#FFFF00', '#FFA500', '#FF0000']}
         slope_map.addLayer(slope_layer, slope_vis_params, "Slope")
         slope_map.add_colorbar(vis_params=slope_vis_params, label="Slope (degrees)")
+        
+        slope_map.addLayerControl()
+        slope_map_html = slope_map._repr_html_()
+
     except Exception as e:
         print(f"Error creating Slope map: {e}")
         slope_map_html = f"<div>Error creating Slope map: {e}</div>"
 
-    slope_map.addLayerControl()
-    slope_map_html = slope_map._repr_html_()
-
     return dem_map_html, slope_map_html
 
-
 def add_indices(image, nir_band, red_band, blue_band, green_band, evi_vars):
     """Calculates and adds multiple vegetation indices to an Earth Engine image."""
     # It's safer to work with the image bands directly
@@ -331,25 +333,19 @@ def process_and_display(file_obj, url_str, buffer_m, progress=gr.Progress()):
 
     progress(0, desc="Reading and processing geometry...")
     try:
+        # ... (no changes to the geometry processing part) ...
         input_gdf = get_gdf_from_file(file_obj) if file_obj is not None else get_gdf_from_url(url_str)
         input_gdf = preprocess_gdf(input_gdf)
-
-        # Find the first valid polygon
         geometry_gdf = next((input_gdf.iloc[[i]] for i in range(len(input_gdf)) if is_valid_polygon(input_gdf.iloc[[i]])), None)
-
         if geometry_gdf is None:
             return None, "No valid polygon found in the provided file.", None, None, None, None, None
-
         geometry_gdf = to_best_crs(geometry_gdf)
-
-        # Create buffer
         outer_geometry_gdf = geometry_gdf.copy()
         outer_geometry_gdf["geometry"] = outer_geometry_gdf["geometry"].buffer(buffer_m)
         buffer_geometry_gdf = gpd.GeoDataFrame(
             geometry=[outer_geometry_gdf.unary_union.difference(geometry_gdf.unary_union)],
             crs=geometry_gdf.crs
         )
-
     except Exception as e:
         return None, f"Error processing file: {e}", None, None, None, None, None
 
@@ -368,13 +364,15 @@ def process_and_display(file_obj, url_str, buffer_m, progress=gr.Progress()):
             .replace("{TileCol}", "{x}")
         )
         
-    # Convert to EE geometry for DEM/Slope maps
-    ee_geometry = ee.Geometry(json.loads(geometry_gdf.to_crs(4326).to_json())['features'][0]['geometry'])
-    dem_html, slope_html = get_dem_slope_maps(ee_geometry, wayback_url, wayback_title)
-
-    # Create main map with folium
+    # **NEW**: Calculate map center from the geometry's bounds
     bounds = geometry_gdf.to_crs(epsg=4326).total_bounds
     map_center = [(bounds[1] + bounds[3]) / 2, (bounds[0] + bounds[2]) / 2]
+
+    # **MODIFIED**: Pass map_center to the function
+    ee_geometry = ee.Geometry(json.loads(geometry_gdf.to_crs(4326).to_json())['features'][0]['geometry'])
+    dem_html, slope_html = get_dem_slope_maps(ee_geometry, map_center, wayback_url=wayback_url, wayback_title=wayback_title)
+
+    # Create main map with folium using the calculated center
     m = folium.Map(location=map_center)
     
     if wayback_url:
@@ -384,17 +382,14 @@ def process_and_display(file_obj, url_str, buffer_m, progress=gr.Progress()):
     m.add_child(folium.LayerControl())
     m.fit_bounds([[bounds[1], bounds[0]], [bounds[3], bounds[2]]])
 
-    # Generate stats
+    # ... (rest of the function remains the same) ...
     stats_df = pd.DataFrame({
         "Area (ha)": [f"{geometry_gdf.area.item() / 10000:.2f}"],
         "Perimeter (m)": [f"{geometry_gdf.length.item():.2f}"],
         "Centroid (Lat, Lon)": [f"({geometry_gdf.to_crs(4326).centroid.y.iloc[0]:.6f}, {geometry_gdf.to_crs(4326).centroid.x.iloc[0]:.6f})"]
     })
-
-    # Save geometry data for later use
     geometry_json = geometry_gdf.to_json()
     buffer_geometry_json = buffer_geometry_gdf.to_json()
-
     progress(1, desc="Done!")
     return m._repr_html_(), None, stats_df, dem_html, slope_html, geometry_json, buffer_geometry_json