From Brad Christiansen, "To build OSG using Visual Studio 2010 Terrain.cpp requires #include <iterator>. This is a very common fix when using 2010 due to changes in Microsoft STL.

"

src/osgTerrain/Terrain.cpp

@@ -15,6 +15,8 @@
 #include <osgTerrain/GeometryTechnique>
 #include <osgUtil/UpdateVisitor>
 
+#include <iterator>
+
 #include <OpenThreads/ScopedLock>
 
 using namespace osg;