Abstract: Under a transparent board-like digitizer, a screen of the same size as that of the digitizer is positioned. Scenes of a display device is shown on the screen. A co-ordinates standard of the digitizer is set to be identical with that of the screen. Consequently, the point indicated on the digitizer of a first cursor device is shown at a position corresponding to that of the point indicated by means of the cursor. In a circle drawing mode of the digitizer, when the operator places the cursor device on the digitizer and co-ordinates data are inputted to a computer, a plot circle corresponding to the co-ordinates data is displayed on the screen. When the operator makes the plot circle by means of the cursor device, the computer selects a radial input system. On the other hand, when the operator uses the cursor device and selects the exterior of the plot circle, a transient point input system is selected.

Abstract: A transparent board-like digitizer is placed near a display screen. Images of the same size as that of the digitizer images entered on the digitizer are displayed on the screen. A co-ordinates standard of the digitizer is set to be identical with that of the screen. Thereby, the point indicated on the digitizer of a first cursor device is shown at a position corresponding to that of the point indicated by the cursor. The screen displays right-angle scale lines controlled by a second cursor device on the digitizer. The right-angle scale lines can carry out parallel movements and rotations on the screen.