diff --git a/lidar_pipeline/rendering.py b/lidar_pipeline/rendering.py
index eaae0c0..626ce34 100644
--- a/lidar_pipeline/rendering.py
+++ b/lidar_pipeline/rendering.py
@@ -200,6 +200,10 @@ def _apply_colormap(data, tif_file):
             valid_data = np.asarray(data.compressed() if hasattr(data, 'compressed') else data.flatten())
             valid_data = valid_data[~np.isnan(valid_data)]
 
+            if len(valid_data) == 0:
+                logger.warning(f"    Aucune donnée valide pour {Path(tif_file).name} — colormap ignorée")
+                return data, 'terrain', Path(tif_file).stem.replace('_', ' ').title(), '', '', False
+
             vmin = vmax = None
 
             # Compute vmin/vmax based on mode
@@ -234,6 +238,8 @@ def _apply_colormap(data, tif_file):
     # Default: terrain colormap with percentile stretch
     valid_data = np.asarray(data.compressed() if hasattr(data, 'compressed') else data.flatten())
     valid_data = valid_data[~np.isnan(valid_data)]
+    if len(valid_data) == 0:
+        return data, 'terrain', Path(tif_file).stem.replace('_', ' ').title(), '', '', False
     p2, p98 = np.percentile(valid_data, (2, 98))
     data = np.clip((data - p2) / (p98 - p2), 0, 1)
     title = Path(tif_file).stem.replace('_', ' ').title()