Application of GIS: Maritime Accident Analysis in Malaysian Waters Using Kernel Density Function

e-mail: sarahmohdisnan@gmail.com Statistics from the Marine Department in Malaysian Territorial waters has shown an increase in maritime accidents. The data of maritime accidents, including latitude and longitude of the locations, are analysed using Geographical Information System with Kernel Density function. This is to visualise, locate and identify the high-risk location of maritime accidents in Malaysian waters. Using the GIS analysis, the findings suggest that the data of the high-risk maritime location is at Malacca Straits. The results showed that GIS analysis is a useful tool to analyse maritime accidents data and can be used as a guidance for navigators to plan their passage in order to avoid maritime accidents. Application of GIS: Maritime Accident Analysis in Malaysian Waters Using Kernel Density Function


LITERATURE REVIEW
Most of the scholars focused on the analysis of the maritime accidents data using GIS such as Huang et al., (2013), Acharya et al., (2017) and Zhang et al., (2020). Both Huang et al., (2013) and Acharya et al., (2017) used Buffer analysis to study distribution of maritime accidents. On the other hand, Zhang et al., (2020) used Kernel Density analysis to study distribution patterns of maritime accidents worldwide. Ugurlu et al., (2012) and Sigua & Aguilar (2003) created a new database of ship accidents using GIS. Dobbins and Abkowitz (2010) simulated ship routes using GIS in order to analyse ship traffic in the US waters.
Based on the literature review, most of the researchers have used GIS to analyse maritime accidents, but they have only emphasised general global maritime accidents in certain areas. However, no research on GIS analysis has been done in Malaysian waters. Hence, this research is important to visualise and map out the trends of maritime accidents in Malaysian waters. This will help in future coastal planning and safety management, as well as decision making.

Spatial Analysis in GIS
In GIS, spatial data that contains attributes can be visualised in a map to predict an incident by an interactive method. Different layers of maps which contain different spatial data and attributes could be combined to produce a single map. The spatial analysis is a tool in ArcGIS which is able to visualise and model the spatial data geographically. In addition, the output can be explored to predict any upcoming situation. This analysis is powerful in assessing the topographical suitability of different purposes, making predictions of output, and analyse and interpret the changes occurring based on the results produced, so that users can solve the problem efficiently (Esri, 2018).

Kernel Density Analysis
Geographic information system is a computer system designed to capture, query, analyse, and display geospatial data (K.T Chang, 2019). Kernel density analysis is one of the tools in GIS that is used for hot spot analysis. This method analyses location and spatial extent of incidents accurately. Statistically, Kernel density technique is a better hot spot identifier than the cluster analysis techniques (Shahrabi and Pelot, 2009). Kernel density method generalises incident occurrences over the entire study area, while hot spot techniques provide statistical summaries for the incidents (Shahrabi and Pelot, 2009). This method calculates densities in all locations, whereas other hot spot analysis defines the boundary of hot spot areas arbitrarily (Shahrabi and Pelot, 2009). Kernel density method creates a continuous surface to represent density variability over the entire study area, not just in certain cluster, as is the case with other hot spot techniques (Shahrabi and Pelot, 2009).
The estimation for new coordinates at a point (m,n) is shown in Figure 1. The predicted density at a new (x,y) location is determined by the following formula:

Study Area
The study area focuses on Malaysian waters. Data from the Marine Department consists of four different years of accident (2016 to 2019), types of vessels, type of accidents, longitude and latitude of location of accidents. The data is then processed in ArcMap, which shows the latitude and longitude of each accident. Subsequently, the map is analysed using GIS Kernel Density Analysis to predict the vulnerable area of maritime accidents in order to improve safety management planning. The raw data that was received from the Marine Department of Malaysia has undergone quality checking to ensure accurate attributes and spatial data. After that, the latitude and longitude are converted into radian format, so that the GIS will be able to map and visualise the data in an interactive map. The work process of the research is shown in Figure 2   and adrift. In 2018, the majority of accidents were related to vessel explosion, and the lowest were adrift and man overboard. The highest number of accidents occurring in 2019 was vessel collision, while the lowest was man overboard and adrift. According to Ezequiel and Marin (2014), even with advanced technologies and management, any type of maritime accident, such as collision, explosion, and sinking can happen.

Figures 4 and 5 show maritime accidents in Malaysia during
the year 2018, after Kernel Density analysis was done. The high occurrence of accidents is reported at Singapore Straits and Sarawak territorial sea. The result of Kernel Density function analysis has produced different types of contour to indicate the highest to the lowest risk of accidents. Firstly, the dark blue label indicates the lowest or low-risk area of accidents. Next, the label that is pink in colour indicates moderate risk area of accidents. The red label indicates the areas that are categorised as risky. Finally, the high-risk area is highlighted with a darker red colour. More than 100,000 ships navigate through the Straits of Malacca annually. It has a high traffic density as it is the shortest route for vessels from the Middle East to China (Abdul Wahab, 2017).
One of the possible causes of accidents at Malacca Straits is the restricted visibility due to haze caused by forest and bush fires in Sumatra. This has affected the safe navigation through the waterways, and it remains a threat to mariners even today.
Other than that, groundings are also one of the frequent accidents along the Straits. With the shallow seafloor along the Singapore Straits being the most notorious for groundings, some ships get stuck while navigating along the stretches of the Malacca Straits (Ahmad, 2014). On top of that, ships that are not adequately maintained or are suffering mechanical problems contribute to the risk of accidents. A power or steering failure while navigating busy or challenging waters can quickly turn into a severe situation (Fadzlon, n.d.).
Trans. marit. sci. 2021; 02: 348-354     Based on Kernel Density Analysis, high risk and very highrisk locations are at Straits of Malacca and Singapore Straits. In addition, the Straits' most difficult conditions lie between Horsburgh Lighthouse and One Fathom Bank Lighthouse, about 217 miles away. Moderate risk is recorded for this area. The remaining 500 miles are more accessible to the sea. As masters are free to plan their course, the apparent trend is to use the shortest route. This means that many ships draw the same courses that cause them to overtake the narrow limits of the lane. Although the implementation of Traffic Separation Schemes (TSS) has considerably assisted traffic management, with different types of vessels travelling at different speeds and crews, there is still a risk of collision and grounding (Fadzlon, n.d.).
In Kedah waters, kernel density analysis detects intermediate risk and moderate risk area of maritime accidents. This is because vessels seldom cross this area. Based on the analysis, maritime accidents at Sarawak and Sabah are moderate to low. Navigators seldom cross this waterway as they usually use Malacca Straits, being the shortest route to cross from the Middle East to China (Abdul Wahab, 2017).

CONCLUSION
Kernel Density analysis function in ArcMap is able to produce an output of map with the analysis of dense maritime accidents location. Geographical Information System is able to produce output of the pointed location of maritime accidents and analysis of the highest and lowest number of the accidents. From this research, any agencies or government may be able to improve the safety on sea by surveying the location that has high a number of accidents and avoiding them. Navigators also need to be extra careful when navigating through the Straits of Malacca.
For the recommendation of future research, the researcher suggests adding details of the location of maritime accidents information on the ArcMap. Details such as water depth, navigation equipment like buoys and lighthouses, tidal stream and current, as well as location of anchorage, could be added so that the ArcMap will be more helpful to navigators in planning their passage to avoid maritime accidents.