use o maker

visualize.py

@@ -70,7 +70,7 @@ def plot_global_map_static(df, lat_col='centre_lat', lon_col='centre_lon'):
     df_clean = df_clean.dropna(subset=[lat_col, lon_col])
     
     # Sample every 3rd item if too large
-    if len(df_clean) > 50000:
+    if len(df_clean) > 250000:
         # Calculate step size to get approximately 50000 samples
         step = 2
         # step = max(1, len(df_clean) // 50000)
@@ -94,11 +94,11 @@ def plot_global_map_static(df, lat_col='centre_lat', lon_col='centre_lon'):
     ax.scatter(
         df_vis[lon_col],
         df_vis[lat_col],
-        s=0.4,
-        c='blue',
-        marker='s',
+        s=0.2,
+        c="blue",
+        marker='o',
         edgecolors='none',
-        alpha=0.5,
+        # alpha=0.6,
         transform=ccrs.PlateCarree(),
         label='Samples',
     )