Abstract:

Nautical Chart is an important navigational instrument that represents water depth, ground elevation, seafloor characteristics, shoreline characteristics, man-made structures, flow information, tides and other characteristics. However, these features can be continuously altered by human activities and natural fluctuations. Therefore, using old Nautical Chart days for navigation may lead to serious consequences. Furthermore, the accuracy and effectiveness of Nautical Chart must ensure that any navigational access to the port is guaranteed. Recently, there are a variety of charting methods, ranging from traditional methods such as Multi-Beam Echo-Sounder (MBES) to modern methods like Light Detection and Ranging (LiDAR). Although both of these techniques provide high accuracy and dense coverage of in-depth measurements, they require high investment costs and are difficult to be applied in shallow waters. This paper presents a study on applying Landsat-8 images to determine the depth for shallow coastal waters and update the charts in the coastal area of Da Nang Bay and surrounding areas. Experiments and calculation results show that the Root-mean square error of the standard model, in meters (RMSE), is about 10% of the actual depth and also illustrate a very high correlation to the depth of less than 20 m. Therefore, this method can be identified as an efficient and economical way to ensure the accuracy of nautical charts without doing MBES or LiDAR survey in Viet Nam coastal regions if there is enough high- resolution satellite image data such as Worldview 1,2,3 (0.5m) or GeoEye-1 (0.5m)…for input.