Abstract: An image display unit 10 comprises a light source 14 and a light diffusing panel 18, over which is mounted an opposed pair or retaining sheets 20 with a volume 22 formed between each retaining sheet 20 and the panel 18 for receiving an image-bearing sheet 34. An elongate opening 26, 28 for providing access to the volume 22 formed in each face of the unit 10 is located spaced from the edges of the unit 10, so allowing a user to access the volumes 22 regardless of proximity of the edges of the unit 10 to other units, or to a wall or the like.

Abstract: A mapping system is provided comprising a plurality of display panels (8) located at or on a ceiling of a building such as a supermarket. The panels (8) form a network of routes through the supermarket, with each panel illustrating the content of the supermarket aisle (4) adjacent the panel (8). The elevated nature of the panels (8) allows users to identify the content of aisles (4) distant from their current location, and users may thus identify a route leading to the selectred aisle as well as the contents of aisles along which the route passes. A number of alternative embodiments of the invention are described, together with methods of guiding individuals around environments using maps of the invention.