Abstract: In the navigation display of the electronic flight instrument system, the arc mode and Rose Nav mode of a navigation display require computation of parameters for a greater surface (modified Edit) area than the Edit area for each display scale. When the icons representing selected navigational features are included on the navigation display, the retrieved and stored icons can be positioned external to the viewable Edit area. Because access to a dictionary defining the position of the icons is sequential and because the display buffer storage unit from which the screen display is created has a limited capacity, the arc or Rose Nav display can include features in the non-viewable modified Edit area while not including important features in the Edit area. An algorithm is described that determines when a feature with which an icon is associated is in the Edit area and selects the data associated with those features in the Edit area to be stored in the display buffer storage unit.