| 摘要 |
PURPOSE: To display a position of one's own ship and a target position on a screen at all times without any manipulation however the ship is separated from the target position, by setting a target position-setting key, a target position memory means, a target position display means and a reduction scale change means, etc. CONSTITUTION: A first reduction scale-determining means 202 and a target position display means 203 are installed in a read only memory 102, and a target position memory means 204 is set in a memory 103. At the same time, a target position-setting key 205 is set in an input means 104. When the target position-setting key 205 is depressed, the first reduction scale-determining means 202 and the target position display means 203 are excited thereby to display a screen center and a target position. Meanwhile, a second sea zone determined by one smaller reduction scale than the presently set reduction scale is set in a display range memory means 113. When one's own ship approaches the target position and enters the sea zone, a second sea zone-detecting means 206 detects the state. The detection excites a second reduction scale-determining means 207 and changes the reduction scale to one larger value. |
