## 3 Methodology
### Analysis of the Land Conversion Matrix  
With Hong Kong original construction land unchanged between 1980 and 1990, a total of 27.48 km\({}^{2}\) was transferred from the four types of cultivated land, sea area, water area, and forest land, and the construction land increased to 176.42 km\({}^{2}\). Among them, the area of cultivated land converted to construction land was the largest (13.27 km\({}^{2}\)), followed by sea area (7.2 km\({}^{2}\)) and water area (3.95 km\({}^{2}\)); the area of forest land converted to construction land was the least (3.06 km\({}^{2}\)) (Table 4). From the spatial perspective, conversion areas were mainly concentrated in Tuen Mun and Yuen Long districts, with a few reclamation projects in the coastal areas of Sham Shui Po and Tai Po. \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Land Use Type**} & **Cultivated Land** & \multirow{2}{*}{**Forest Land**} & \multirow{2}{*}{**Grassland**} & \multirow{2}{*}{**Water Area**} & **Construction Land** & **Unused Land** & **Sea Area** \\ \hline Cultivated & & & & & & \\ land & 66.763 & 0.0018 & 0 & 0 & 13.27 & 0 & 0 \\ Forest land & 0.0036 & 642.26 & 0.0018 & 0 & 3.06 & 0 & 0 \\ Grassland & 0 & 0.0054 & 166.77 & 0 & 0 & 0 & 0 \\ Water area & 0 & 0 & 0 & 42.86 & 3.95 & 0 & 0 \\ Construction & 0 & 0 & 0 & 0 & 148.42 & 0 & 0 \\ land & 0 & 0 & 0 & 0 & 0.1026 & 0 \\ Sea area & 0 & 0.0054 & 0 & 0.8892 & 7.20 & 0 & 22.73 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Land Use Transformation Matrix, 1980–1990 (km\({}^{2}\)). The area of construction land maintained a rapid increasing trend from 1990 to 2000, with a total of 32.94 km\({}^{2}\) transferred from land types such as cultivated land, forest land, sea area, and other land types, among which sea area transferred the largest area, followed by forest land and cultivated land (Table 5). Spatially, the transfer of sea area to construction land (17.48 km\({}^{2}\)) was mainly due to the large-scale reclamation project of the Hong Kong Airport and the West Kowloon Reclamation Project, while the transfer of forest land and cultivated land to construction land was mainly concentrated in Yuen Long District. In addition, a small amount of construction land was transferred out, mainly from construction land to forest land and cultivated land, which was mainly distributed in the southwest of Tuen Mun District. The construction land increased to 234.14 km\({}^{2}\) from 2000 to 2010; cultivated land (21.14 km\({}^{2}\)), forest land (18.16 km\({}^{2}\)), and sea area (14.82 km\({}^{2}\)) were the most transferred areas, followed by grassland and water area (Table 6). Spatially, the conversion of cultivated land to construction land was mainly concentrated in the entire Yuen Long District, with a small amount distributed in the North District, and the conversion of forest land to construction land was mainly concentrated in the west of the North District. The conversion of sea areas to construction land was mainly concentrated in the northern part of Hong Kong Island, which was due to the long-established Central Reclamation Project. In this decade, the area transferred from construction land was 24.14 km\({}^{2}\); the greatest area was converted to grass and forest, followed by cultivated land and water area. The growth rate of construction land slowed down and the area increased to 236.32 km\({}^{2}\) until 2020, with the largest area of forest land converted to construction land (7.86 km\({}^{2}\)), followed by cultivated land and sea area (Table 7). Spatially, the conversion of forest land to construction land was mainly located at the junction of Kwun Tong and Sai Kung districts, with a small amount scattered throughout Hong Kong; the conversion of cultivated land to construction land was also scattered throughout Hong Kong. In addition, the conversion of cultivated land to construction land was also scattered in various districts of Hong Kong. The main reason for the conversion of sea areas to construction land was the reclamation