| 摘要 |
PURPOSE:To correct overall deviation due to errors in a position measuring apparatus, by measuring and calculating the depth in addition to the position of a ship to determine a chart on the depth in the perimeter of the track thereof, which is displayed being superimposed on a sea bottom topographical map. CONSTITUTION:In addition to the position of a ship F, the depth is measured and calculated with a depth measuring device B to determine a chart on the depth of the track or in the perimeter thereof. The depth chart is shown on a display being superimposed on a sea bottom topographical map memorized by a memory means. Thus, the overall deviation due to errors of a position measuring device is corrected by a visual judgement or alteration of the display position of either the depth chart or the sea bottom topographical map to find the position of the ship accurately. |
