# A System to Improve Port Navigation Safety and Its Use in Italian Harbours
## 3 Results  
The system, even if it is still a prototype, was tested on some real events that occurred in Livorno and Bari harbours, achieving satisfactory results in signalling potentially dangerous conditions for a certain ship at a given instant. In Figure 14a the center of the map of the port of Livorno is updated by means of data acquired on 24 February 2020 at 02:20; on the contrary, Figure 14b is referred to 5 December 2020 at 12:10; the user interface reports date, time and sea level of each measurement read from the archive. As we can see, sea level rises from \(-0.37\) to 0.68 m; the consequent increase in sea level equal to 1.05 m causes an enlargement of the allowed area (in particular the green waterway in the middle of the map) and a reduction of the prohibited (red) one (the increase in sea level is partly due to astronomical tide and partly to a decrease in atmospheric pressure which changes approximately from 1023.9 to 994.8 hPa; pressure data at 24 February at 02:20 and on 5 December at 12:10 have been calculated by extrapolating the adjacent hourly measurements). In Figure 15 the lower central area of Bari harbour is updated according to the values measured on 24 July 2020: in Figure 15a the map is at 17:30, while Figure 15b is referred at 23:30; the sea level is equal to 0.14 m in the first case, and it is to--0.38 m in the second case: then, there is a gradient of--0.52 m between the two different situations illustrated; this induces shrinkage of the allowed (green) area and an expansion of the prohibited (red) zone; atmospheric pressure rises from about 1007.4 to 1011.5 hPa within a few hours and then contributes to drop the sea level; in particular, we can see that the green waterway in the middle of the map becomes narrower, due to the decrease in the sea level. Furthermore, the user interface shows coordinates and depth of the position pointed by the mouse at each instant; moreover, the traffic light shows by means of the correct colour if that position at the current time belongs to a forbidden, allowed or warning area: by keeping the mouse pointer in a certain position, it is possible to follow the evolution of its state over time. In Figure 14, the bottom depth related to coordinates Easting 605,075, Northing 4,824,140 m pointed by the mouse arrow in the middle of the channel varies from 11.49 to 12.54 m, then the corresponding traffic light turns from red (prohibited position) to green (allowed position) colour (thresholds are fixed to 11.5 and 12.5 m). In the example in Figure 15, on the contrary, the depth of the position Easting 655,971, Northing 4,555,512 m in the middle of the map changes from 10.27 to 9.75 m, so its traffic light changes from green (permitted position) to yellow (warning position) light (higher threshold is equal to 10 m). Therefore, the user interface implements the so-called virtual traffic lights (partition in red, yellow and green areas) customized for each vessel, depending on its draught: varying sea level, an area that initially was allowed (green), can become a warning (yellow) or forbidden area (red) for that ship, or vice versa; this application has been developed to support port communities (coast guards, port authorities, pilots, terminal operators) to plan and optimize coastal navigation (e.g., deciding when a ship can enter/leave a port or to choose its best route), ship moorings and docking performances (e.g., to which quay a vessel can access), logistics operations and ship loading (e.g., establishing the cargo of a vessel at the starting port according to the expected sea level at the destination), effectiveness in maritime works (e.g., dimensioning of breakwaters), and monitoring of water exchange in harbours; above all, it can be a helpful tool to port operators to increase port navigation safety, to prevent ship accidents, to manage emergencies such as ship stranding, or to reduce the risks of environmental damage (dispersion of pollutant) and economic impacts.