Automatic route checking method using post-processing for the measured water depth

An Electronic Navigational Chart (ENC) is a standardized database that can be used with an Electronic Chart Display & Information System (ECDIS) for applications such as navigation warning, efficient route planning for ship navigation, etc. An ENC contains all the required information for ship navigation. Route planning on the ENC is done with a consideration of the depth area, distance with isolated danger area, structures requiring navigation, wrecks, etc. Because route planning has to be done in consideration of these factors, sometimes a route will have a longer distance than the straight line distance. This causes much loss of time and fuel. In order to reduce the loss of time and fuel, it is necessary to have a wide navigation area. The first item of consideration, the depth area, has a decisive effect on route planning. However, the depth area consists of a large interval of about 5 to 10 meters and this interval can cause a gap of several kilometers on the horizontal distance. This means that the navigation area is (narrower than the optimized navigation) not optimal on narrow waterways, has a low slope surplane, and in some cases there are problems with under water topography. This paper suggests a method to obtain an optimized navigation area using water depth information, which has denser depth information than the depth area in the ENC and can be used to verify the method of ECDIS route planning using depth area and water depth information. Water depth in the ENC has more density resolution depth information than does the depth area and is extracted in a triangular shape; no lower sounding depth than the selected depth is allowed within the extracted sounding depth. Considering this characteristic for triangulation, underwater topography formed by triangulation based on water depth applying the Delaunay Algorithm can be used to compare a triangle edge's depth information and the safety depth of a ship in order to classify the triangular safety area. Implementation was performed to compare two ship route plan modules with a consideration of mariner setting on ECDIS. Comparison of the two route plans, which is focused on the route length and the entire expected amount of time spent from the start waypoint to the end waypoint, was used for the verification of the route planning efficiency.