| 摘要 |
The method is for the improvement of a depth data base for a nautical chart and involves a central system (1) incorporating a central nautical chart data base (11), whereby an electronically based nautical chart (21) can be installed in a local system (2) on board a marine vessel (A). The local system incorporates a local nautical chart data base (22) to which information is delivered from the central nautical chart data base, by means of which the electronic nautical chart is maintained. A depth measurement unit (23) forms part of the local system and collects depth information (23a). A position measurement unit (24) in the local system collects positioning information (24a). The measured depth and positioning information contains theoretical values (25a) which are used to substantiate and where necessary to correct or complete available information from the local nautical chart data base. The theoretical values are stored in a local correction data base (25) and one or more of them can be used for correction or completion of the central nautical chart data base. |
