arcengine在arcglobe中实现缩放至图层

//创建3D显示层 
public void create3Dlayer(string layername) 
{ 
    m_globeGraphicsLayer = new GlobeGraphicsLayerClass(); 
    ((ILayer)m_globeGraphicsLayer).Name = layername;

    IScene scene = (IScene)m_globeDisplay.Globe;

    //Add the new graphic layer to the globe. 
    scene.AddLayer((ILayer)m_globeGraphicsLayer, false);

    //Activate the graphic layer. 
    scene.ActiveGraphicsLayer = (ILayer)m_globeGraphicsLayer;

}