Update app.py

app.py

@@ -98,12 +98,23 @@ def visualizar_grafo():
     if len(G.nodes) == 0:
         print("⚠️ Warning: The graph is empty! Check if data was loaded correctly.")
         plt.text(0.5, 0.5, "No data available", fontsize=12, ha='center')
+        plt.savefig("graph.png")
+        plt.close()
+        return "graph.png"
+
+    # 📌 1. Calcular betweenness centrality
+    centrality = nx.betweenness_centrality(G)
+    pos = nx.kamada_kawai_layout(G)  
+    node_sizes = [2000 + 8000 * centrality[node] for node in G.nodes()]  # Tamaño base 2000, escalar con betweenness
+    nx.draw(
+        G, pos, with_labels=True, node_color='lightblue', edge_color='gray',
+        node_size=node_sizes, font_size=10
+    )
     
-    pos = nx.spring_layout(G)
     edge_labels = nx.get_edge_attributes(G, 'label')
-    nx.draw(G, pos, with_labels=True, node_color='lightblue', edge_color='gray', node_size=2000, font_size=10)
     nx.draw_networkx_edge_labels(G, pos, edge_labels=edge_labels, font_size=8)
-    plt.title("Red de Aportes")
+    
+    plt.title("Red de Aportes - Optimizada por Betweenness")
     plt.savefig("graph.png")
     plt.close()