Abstract: A user interface system for controlling an electronic device having a touch-screen. The system is configured: to detect and identify sliding contact by a user at a contact point on the touch-screen, wherein the sliding includes the contact point being moved in a first direction, and to scroll displayed content substantially in the first direction; and to detect and identify simultaneous sliding contact by the user at two contact points on the touch-screen, wherein the sliding including the contact points being moved substantially parallel to a common axis, and to cause a non-scrolling change in the displayed content in response to said detection of simultaneous sliding. The non-scrolling change might, for example, be the angle of inclination of an inclined perspective projection. The displayed content could be a map.