/**
* Set the object to use to draw catalog symbols
*/
public void setCanvasGraphics(CanvasGraphics canvasGraphics) {
_imageGraphics = (DivaImageGraphics) canvasGraphics;
NavigatorPane pane = (NavigatorPane) _imageGraphics.getGraphicsPane();
_layer = pane.getSymbolLayer();
pane.getBackgroundEventLayer().addLayerListener(this);
}