1. A navigation device comprising: a route calculation module operable to calculate a route from a start location to a destination location; a rendering module configured to use digital map data to generate images of said route for display to a user; and a route preview module operable to provide the user with a preview of the calculated route, wherein: the route preview module is operable to divide said calculated route into junction segments and road segments, and is configured to control said rendering module to display images representative of locations within said road segments at a higher display speed than images representative of locations within said junction segments.