/**
   * Causes resources used by the World Window to be freed. The World Window cannot be used once
   * this method is called. An OpenGL context for the window must be current.
   */
  public void shutdown() {
    WorldWind.getDataFileStore().removePropertyChangeListener(this);

    if (this.inputHandler != null) {
      this.inputHandler.dispose();
      this.inputHandler = new NoOpInputHandler();
    }

    // Clear the texture cache
    if (this.getGpuResourceCache() != null) this.getGpuResourceCache().clear();

    // Dispose all the layers //  TODO: Need per-window dispose for layers
    if (this.getModel() != null && this.getModel().getLayers() != null) {
      for (Layer layer : this.getModel().getLayers()) {
        try {
          layer.dispose();
        } catch (Exception e) {
          Logging.logger()
              .log(
                  java.util.logging.Level.SEVERE,
                  Logging.getMessage("WorldWindowGLCanvas.ExceptionWhileShuttingDownWorldWindow"),
                  e);
        }
      }
    }

    SceneController sc = this.getSceneController();
    if (sc != null) sc.dispose();
  }
    public void doActionOnButton4() {
      ArrayList<LatLon> locations = new ArrayList<LatLon>();

      locations.add(LatLon.fromDegrees(45.50d, -123.3d));
      locations.add(LatLon.fromDegrees(45.52d, -123.3d));
      locations.add(LatLon.fromDegrees(45.54d, -123.3d));
      locations.add(LatLon.fromDegrees(45.56d, -123.3d));
      locations.add(LatLon.fromDegrees(45.58d, -123.3d));
      locations.add(LatLon.fromDegrees(45.60d, -123.3d));

      locations.add(LatLon.fromDegrees(40.50d, -120.1d));
      locations.add(LatLon.fromDegrees(40.52d, -120.2d));
      locations.add(LatLon.fromDegrees(40.54d, -120.3d));
      locations.add(LatLon.fromDegrees(40.56d, -120.4d));
      locations.add(LatLon.fromDegrees(40.58d, -120.5d));
      locations.add(LatLon.fromDegrees(40.60d, -120.6d));

      // Now, let's find WMSBasicElevationModel
      WMSBasicElevationModel wmsbem = null;

      ElevationModel model = this.wwd.getModel().getGlobe().getElevationModel();
      if (model instanceof CompoundElevationModel) {
        CompoundElevationModel cbem = (CompoundElevationModel) model;
        for (ElevationModel em : cbem.getElevationModels()) {
          // you can have additional checks if you know specific model name, etc.
          if (em instanceof WMSBasicElevationModel) {
            wmsbem = (WMSBasicElevationModel) em;
            break;
          }
        }
      } else if (model instanceof WMSBasicElevationModel) {
        wmsbem = (WMSBasicElevationModel) model;
      }

      if (null != wmsbem) {
        ElevationsRetriever retriever =
            new ElevationsRetriever(wmsbem, locations, 10000, 30000, new NotifyWhenReady());
        retriever.start();
      } else {
        String message =
            Logging.getMessage(
                "ElevationModel.ExceptionRequestingElevations",
                "No instance of WMSBasicElevationModel was found");
        Logging.logger().severe(message);
      }
    }
 public void onError(String error) {
   String message = Logging.getMessage("ElevationModel.ExceptionRequestingElevations", error);
   Logging.logger().severe(message);
 }