Lee, J.K.; Lee, I., and Kim, J.O., 2017. Analysis on tidal channels based on UAV photogrammetry: Focused on the west coast, South Korea case analysis. In: Lee, J.L.; Griffiths, T.; Lotan, A.; Suh, K.-S., and Lee, J. (eds.), The 2nd International Water Safety Symposium. Journal of Coastal Research, Special Issue No. 79, pp. 199–203. Coconut Creek (Florida), ISSN 0749-0208.
In the coastal waters of the Republic of Korea, the incidence of marine vessel accidents has been increasing in recent years, due to increased maritime traffic and complex terrain conditions. With the proliferation of marine leisure activities and the maritime conditions such as tides, rocks, typhoons, tsunamis, there are various types of marine accidents that have not been experienced before. Therefore, it is imperative to establish an information based system (like digital map or 3D distribution map) that can be utilized in marine safety fields such as accident and disaster prevention. In this investigation, it will be discussed the safety mapping for tidal channel connected directly with human life. A tidal channel is a waterway where occurs by the process of ebb tide and flood tide in the tidal flats. Since the shape (included exact depth) of tidal channel cannot be identified when a tide comes in, it must be considered as the main causes of the summer drowning fatalities. A map for tidal channel has been proposed by a 3D distribution map that can be identified the shape and location of tidal channel, and also, this map should be offered to marine tourist and maritime safety authority. A cartography based on image collected by manned aerial Photogrammetry or satellite has the insoluble limitations in terms of economy, time constraint and periodic for measurement. Due to temporary erratic overflow through the tidal amplitude, the information for tidal channel cannot be monitored in real time. Therefore, in the present investigation, a UAV (Unmanned Aerial Vehicle) recently been actively used in the field of spatial information is considered in analyzing the status of tidal channel. First of all, the DEM (Digital Elevation Model) of tidal flats generates through UAV based auto-image, the distribution map for tidal channel expresses different colors by the height of topographic. A tidal channel encoding specific color (normally red) can be provided dangerous signal to the user. It can be identified the sea leveling at the certain time that can be measured whole shape of tidal channels, and also, provided a more realistic and readable information on tidal flats. The information provided through the tidal channel map was verified by comparison with the VRS GPS positioning solution. Since information such as the exact distribution location and shape should be considered as the first priority, the coordinates of the tidal channel was compared with the previously proven method, VRS GPS. As a result, it is determined that the location of attribute information and the 3D shape analysis value analyzed by UAV image can fully provide information within the convergence range. In this investigation, UAV image can be estimated on the location and shape of tidal channel by observing exactly at the time zone for flood tide. It can be fully expected that the UAV is contributed to preventing the marine accident in advance by maximizing the latent properties with regards to periodicity, accuracy, operation convenience and economy.