From John Vidar Larring, "Added vertical scale as a property of osgTerrain::Terrain. Lets you configure vertical scale when initializing the terrain model. E.g:

osgTerrain::Terrain* terrain = findTopMostNodeOfType<osgTerrain::Terrain>(model.get());
  if (!terrain)
  {
      terrain = new osgTerrain::Terrain;
      terrain->addChild(model.get());
      terrain->setVerticalScale(2.0f);
      model = terrain;
  }
  viewerWindow->setSceneData(model.get());
"

include/osgTerrain/Terrain

@@ -38,12 +38,26 @@ class OSGTERRAIN_EXPORT Terrain : public osg::Group
         
         /** Set the sample ratio hint that TerrainTile should use when building geometry.
           * Defaults to 1.0, which means use all original sample points.*/
-        void setSampleRatio(float ratio) { _sampleRatio  = ratio; }
+        void setSampleRatio(float ratio) 
+        { 
+            _sampleRatio  = ratio;
+            dirtyRegisteredTiles();
+        }
 
         /** Get the sample ratio hint.*/
         float getSampleRatio() const { return _sampleRatio; }
 
 
+        /** Set the vertical scale hint.*/
+        void setVerticalScale(float scale) 
+        { 
+            _verticalScale = scale;
+            dirtyRegisteredTiles();
+        }
+    
+        /** Get the vertical scale hint.*/
+        float getVerticalScale() const { return _verticalScale; }
+        
         /** Get the TerrainTile for a given TileID.*/
         TerrainTile* getTile(const TileID& tileID);
 
@@ -56,6 +70,8 @@ class OSGTERRAIN_EXPORT Terrain : public osg::Group
         
         friend class TerrainTile;
         
+        void dirtyRegisteredTiles();
+
         void registerTerrainTile(TerrainTile* tile);
         void unregisterTerrainTile(TerrainTile* tile);
 
@@ -63,6 +79,7 @@ class OSGTERRAIN_EXPORT Terrain : public osg::Group
         typedef std::set< TerrainTile* >            TerrainTileSet;
 
         float                               _sampleRatio;
+        float                               _verticalScale;
 
         mutable OpenThreads::Mutex          _mutex;
         TerrainTileSet                      _terrainTileSet;

src/osgTerrain/GeometryTechnique.cpp

@@ -278,7 +278,7 @@ void GeometryTechnique::generateGeometry(Locator* masterLocator, const osg::Vec3
     
 
     float minHeight = 0.0;
-    float scaleHeight = 1.0;
+    float scaleHeight = _terrainTile->getTerrain() ? _terrainTile->getTerrain()->getVerticalScale() : 1.0f;
 
     // allocate and assign tex coords
     typedef std::pair< osg::ref_ptr<osg::Vec2Array>, Locator* > TexCoordLocatorPair;
@@ -341,7 +341,7 @@ void GeometryTechnique::generateGeometry(Locator* masterLocator, const osg::Vec3
                 float value = 0.0f;
                 validValue = elevationLayer->getValidValue(i_equiv,j_equiv, value);
                 // osg::notify(osg::INFO)<<"i="<<i<<" j="<<j<<" z="<<value<<std::endl;
-                ndc.z() = value;
+                ndc.z() = value*scaleHeight;
             }
             
             if (validValue)
@@ -373,7 +373,7 @@ void GeometryTechnique::generateGeometry(Locator* masterLocator, const osg::Vec3
 
                 if (elevations.valid())
                 {
-                    (*elevations).push_back((ndc.z()-minHeight)*scaleHeight);
+                    (*elevations).push_back(ndc.z());
                 }
 
                 // compute the local normal

src/osgTerrain/Terrain.cpp

@@ -18,13 +18,15 @@ using namespace osg;
 using namespace osgTerrain;
 
 Terrain::Terrain():
-    _sampleRatio(1.0)
+    _sampleRatio(1.0),
+    _verticalScale(1.0)
 {
 }
 
 Terrain::Terrain(const Terrain& ts, const osg::CopyOp& copyop):
     osg::Group(ts,copyop),
-    _sampleRatio(ts._sampleRatio)
+    _sampleRatio(ts._sampleRatio),
+    _verticalScale(ts._verticalScale)
 {
 }
 
@@ -69,6 +71,25 @@ const TerrainTile* Terrain::getTile(const TileID& tileID) const
     return itr->second;
 }
 
+void Terrain::dirtyRegisteredTiles()
+{
+    OpenThreads::ScopedLock<OpenThreads::Mutex> lock(_mutex);
+
+    for(TerrainTileSet::iterator itr = _terrainTileSet.begin();
+        itr != _terrainTileSet.end();
+        ++itr)
+    {
+        TerrainTechnique* tt = const_cast<TerrainTile*>(*itr)->getTerrainTechnique();
+    if(tt)
+    {
+        tt->dirty();
+
+            // Force recreation of Geometry
+        // const_cast<TerrainTile*>(*itr)->init();
+    }
+    }
+}
+
 static unsigned int s_maxNumTiles = 0;
 void Terrain::registerTerrainTile(TerrainTile* tile)
 {