diff --git a/simgear/scene/model/CheckSceneryVisitor.cxx b/simgear/scene/model/CheckSceneryVisitor.cxx
index 7d774cfa..ebcc011e 100644
--- a/simgear/scene/model/CheckSceneryVisitor.cxx
+++ b/simgear/scene/model/CheckSceneryVisitor.cxx
@@ -29,7 +29,7 @@
 
 using namespace simgear;
 
-CheckSceneryVisitor::CheckSceneryVisitor(osgDB::DatabasePager* dbp, osg::Vec3 &position, double range)
+CheckSceneryVisitor::CheckSceneryVisitor(osgDB::DatabasePager* dbp, const osg::Vec3 &position, double range)
 :osg::NodeVisitor(osg::NodeVisitor::NODE_VISITOR,
                   osg::NodeVisitor::TRAVERSE_ACTIVE_CHILDREN),
 _position(position), _range(range), _loaded(true), _dbp(dbp)
diff --git a/simgear/scene/model/CheckSceneryVisitor.hxx b/simgear/scene/model/CheckSceneryVisitor.hxx
index c89fc18b..e3e5109f 100644
--- a/simgear/scene/model/CheckSceneryVisitor.hxx
+++ b/simgear/scene/model/CheckSceneryVisitor.hxx
@@ -38,7 +38,7 @@ class SGPagedLOD;
 class CheckSceneryVisitor : public osg::NodeVisitor
 {
 public:
-    CheckSceneryVisitor(osgDB::DatabasePager* dbp, osg::Vec3 &position, double range);
+    CheckSceneryVisitor(osgDB::DatabasePager* dbp, const osg::Vec3 &position, double range);
 
     virtual void apply(osg::Node& node);
     virtual void apply(osg::PagedLOD& node);