_manip->getSettings()->setTetherMode(osgEarth::Util::EarthManipulator:: TETHER_CENTER );                //设置_manip的绑定节点                _manip->setTetherNode( _manip->getTetherNode() ? 0L : _xform.get(), 2.0 );                Viewpoint vp = _manip->getViewpoint();                vp.setRange(5000);                //设置操作器的视点                _manip->setViewpoint(vp);