engleski

Towards a More Accurate Automated Sounding Selection: New Method for Selection of Soundings Alongside Berths and Depth Contours

As a navigational aid, a chart uses symbols to provide pilotage information about the nature and position of features useful to navigators while at the same time retaining a level of clarity and readability. That means that a nautical cartographer needs to employ data generalization so as not to clutter up the chart. Sounding selection is used to find the right balance providing the best sea floor display and highest level of navigational safety with the smallest amount of data. As hydrographic survey contains a vast number of soundings, the process of soundings selection is one of the more challenging. Although the selection process is mostly done manually, there are algorithms developed for automatic selection and software used for chart creation that offer an automatic selection feature. Not all soundings represented on the chart have the same level of importance. Most of the soundings that show potential dangers will be selected by a shallow based selection algorithm. This algorithm selects the shallowest soundings within a user defined radius. However, there are special cases that require additional procedure, mostly manual for selection. Some of those cases are: soundings alongside berths and supportive soundings for depth contours. The latter refer to soundings near depth contours that contain important information about the variations of the seafloor. We tested and compared the shallow based sounding selection algorithm within the dKart Editor and a new algorithm developed in the Hydrographic Institute of the Republic of Croatia by the author, on three different areas: approach chart HR400533 (Šibenski kanal, 1:25 000) for supportive soundings for depth contours, berthing charts HR600M04 (Umag, 1:3 000) and HR600M07 (Rovinj, 1:2 000) for berths soundings. The intent of this effort is to improve the consistency and cartographic disposition of the final sounding selection while minimizing manual manipulation.

Automated Sounding Selection; Soundings Alongside Berths; Soundings Alongside Depth Contours

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