diff --git a/src/osgPlugins/dot/BaseDotVisitor.cpp b/src/osgPlugins/dot/BaseDotVisitor.cpp
index 262ae1559..f0ee16cf0 100644
--- a/src/osgPlugins/dot/BaseDotVisitor.cpp
+++ b/src/osgPlugins/dot/BaseDotVisitor.cpp
@@ -140,17 +140,13 @@ namespace osgDot {
 
   }
 
-  void BaseDotVisitor::handle(osg::Node& node, int id) {
-  }
+  void BaseDotVisitor::handle(osg::Node&, int) {}
 
-  void BaseDotVisitor::handle(osg::Geode& node, int id) {
-  }
+  void BaseDotVisitor::handle(osg::Geode&, int) {}
 
-  void BaseDotVisitor::handle(osg::Group& node, int id) {
-  }
+  void BaseDotVisitor::handle(osg::Group&, int) {}
 
-  void BaseDotVisitor::handle(osg::Group& parent, osg::Node& child, int parentID, int childID ) {
-  }
+  void BaseDotVisitor::handle(osg::Group&, osg::Node&, int, int) {}
 
   void BaseDotVisitor::handleNodeAndTraverse(osg::Node& node, int id) {
     osg::StateSet* ss = node.getStateSet();
@@ -164,20 +160,15 @@ namespace osgDot {
     traverse(node);
   }
 
-  void BaseDotVisitor::handle(osg::StateSet& stateset, int id) {
-  }
+  void BaseDotVisitor::handle(osg::StateSet&, int) {}
 
-  void BaseDotVisitor::handle(osg::Node& node, osg::StateSet& stateset, int parentID, int childID) {
-  }
+  void BaseDotVisitor::handle(osg::Node&, osg::StateSet&, int, int) {}
 
-  void BaseDotVisitor::handle(osg::Drawable& drawable, int id) {
-  }
+  void BaseDotVisitor::handle(osg::Drawable&, int) {}
 
-  void BaseDotVisitor::handle(osg::Drawable& drawable, osg::StateSet& stateset, int parentID, int childID ) {
-  }
+  void BaseDotVisitor::handle(osg::Drawable&, osg::StateSet&, int, int) {}
 
-  void BaseDotVisitor::handle(osg::Geode& geode, osg::Drawable& drawable, int parentID, int childID ) {
-  }
+  void BaseDotVisitor::handle(osg::Geode&, osg::Drawable&, int, int) {}
 
   bool BaseDotVisitor::getOrCreateId( osg::Object* object, int &id ) {
     assert( object );
diff --git a/src/osgPlugins/dot/SimpleDotVisitor.cpp b/src/osgPlugins/dot/SimpleDotVisitor.cpp
index 62831ff62..60fad98d0 100644
--- a/src/osgPlugins/dot/SimpleDotVisitor.cpp
+++ b/src/osgPlugins/dot/SimpleDotVisitor.cpp
@@ -42,7 +42,7 @@ namespace osgDot {
     drawNode( id, "record", "solid", label.str(), "black", "white" );
   }
 
-  void SimpleDotVisitor::handle(osg::Group& parent, osg::Node& child, int parentID, int childID ) {
+  void SimpleDotVisitor::handle(osg::Group&, osg::Node&, int parentID, int childID ) {
     drawEdge( parentID, childID, "setlinewidth(2)" );
   }
 
@@ -53,7 +53,7 @@ namespace osgDot {
     drawNode( id, "Mrecord", "solid", label.str(), "green", "white" );
   }
 
-  void SimpleDotVisitor::handle(osg::Node& node, osg::StateSet& stateset, int parentID, int childID ) {
+  void SimpleDotVisitor::handle(osg::Node&, osg::StateSet&, int parentID, int childID ) {
     drawEdge( parentID, childID, "dashed" );
   }
 
@@ -64,11 +64,11 @@ namespace osgDot {
     drawNode( id, "record", "solid", label.str(), "blue", "white" );
   }
 
-  void SimpleDotVisitor::handle(osg::Geode& geode, osg::Drawable& drawable, int parentID, int childID ) {
+  void SimpleDotVisitor::handle(osg::Geode&, osg::Drawable&, int parentID, int childID ) {
     drawEdge( parentID, childID, "dashed" );
   }
 
-  void SimpleDotVisitor::handle(osg::Drawable& drawable, osg::StateSet& stateset, int parentID, int childID ) {
+  void SimpleDotVisitor::handle(osg::Drawable&, osg::StateSet&, int parentID, int childID ) {
     drawEdge( parentID, childID, "dashed" );
   }