diff --git a/src/@deproj/plot_values_contour.m b/src/@deproj/plot_values_contour.m
index 105bd885223c8d9c50a9a5a8d7a169add0deea20..2fc52c5d5063e0fefa20014203eb83cc5f5132f9 100644
--- a/src/@deproj/plot_values_contour.m
+++ b/src/@deproj/plot_values_contour.m
@@ -16,13 +16,39 @@ function hts = plot_values_contour( obj, values, ax )
     if n_objects > 1000, lw = 1; else, lw = 2; end
 
     [ X, Y, Z ] = obj.to_matrices();
-    hts = patch( ...
-        'XData', X, ...
-        'YData', Y, ...
-        'ZData', Z, ...
-        'FaceVertexCData', values, ...
-        'FaceColor', 'flat', ...
-        'LineWidth', lw, ...
-        'Parent', ax );
+    
+    if isempty( values )
+
+        hts = patch( ...
+            'XData', X, ...
+            'YData', Y, ...
+            'ZData', Z, ...
+            'FaceColor', 'none', ...
+            'EdgeColor', 'k', ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+        
+    elseif ischar( values )
+        
+        hts = patch( ...
+            'XData', X, ...
+            'YData', Y, ...
+            'ZData', Z, ...
+            'FaceColor', 'none', ...
+            'EdgeColor', values, ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+        
+    else
+        
+        hts = patch( ...
+            'XData', X, ...
+            'YData', Y, ...
+            'ZData', Z, ...
+            'FaceVertexCData', values, ...
+            'FaceColor', 'flat', ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+    end
 
 end
diff --git a/src/@deproj/plot_values_junction.m b/src/@deproj/plot_values_junction.m
index 1423d836ce0e445e503d086b4f9ceee216016878..6954b0a5685638c4ebe252669e46cd8e2e3c554c 100644
--- a/src/@deproj/plot_values_junction.m
+++ b/src/@deproj/plot_values_junction.m
@@ -6,13 +6,38 @@ function hts = plot_values_junction( obj, values, ax )
     n_objects = numel( obj.epicells );
     if n_objects > 1000, lw = 1; else, lw = 2; end
     
-    hts = patch( ...
-        'Faces', F, ...
-        'Vertices', V, ...
-        'FaceVertexCData', values, ...
-        'FaceColor', 'flat', ...
-        'LineWidth', lw, ...
-        'Parent', ax );
     
+    if isempty( values )
+
+        hts = patch( ...
+            'Faces', F, ...
+            'Vertices', V, ...
+            'FaceColor', 'none', ...
+            'EdgeColor', 'k', ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+        
+    elseif ischar( values )
+        
+        hts = patch( ...
+            'Faces', F, ...
+            'Vertices', V, ...
+            'FaceColor', 'none', ...
+            'EdgeColor', values, ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+
+    else
+        
+        hts = patch( ...
+            'Faces', F, ...
+            'Vertices', V, ...
+            'FaceVertexCData', values, ...
+            'FaceColor', 'flat', ...
+            'LineWidth', lw, ...
+            'Parent', ax );
+        
+    end
+
 end