Abstract: A digital television of the present invention includes an object information storage section and a key assignment control section. The object information storage section contains one or more numerical attribute values indicative of an attribute(s) of each object in association with the object. The key assignment control section ranks the objects by the one or more attribute values in accordance with a predetermined rule and assigns the objects to the direction keys sequentially as they are ranked. As a result, the user can efficiently select a target object and enjoy improved user operability.

Abstract: An object of the present invention is to draw contour lines according to specified display coordinates and display the lines immediately. In order to achieve this object, a display rectangular coordinate system and an input rectangular coordinate system that correspond to each other are set up for a display face of a liquid crystal display unit and for an input face of a tablet. If an input coordinate is specified on the input face using a predetermined directing device, therefore, a tablet control unit outputs hand-written input coordinate data and corresponding display coordinates are specified. Then, a central control unit creates contour data representing contour lines which enclose the figure composed of the specified coordinate data, on the basis of the data according to control of programs read from a floppy disk and stored in a ROM.