## 3 Results
### Land Use Evolution
#### 3.1.2 Spatial Evolution of Land Use over 40 Years
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Period** & **Class** & **a** & **b** & **c** & **d** & **e** & **f** \\ \hline \multirow{6}{*}{1980–1990} & a & 77.47\% & **11.80\%** & 5.99\% & 1.21\% & 2.70\% & 0.81\% \\  & b & **9.13\%** & 82.44\% & 7.34\% & 0.44\% & 0.29\% & 0.36\% \\  & c & 3.20\% & **5.45\%** & 90.19\% & 0.30\% & 0.09\% & 0.76\% \\  & d & **8.79\%** & 3.64\% & 1.92\% & 83.69\% & 0.89\% & 1.07\% \\  & e & **33.75\%** & 4.75\% & 2.51\% & 2.26\% & 56.04\% & 0.68\% \\  & f & 0.49\% & 0.38\% & **1.03\%** & 0.79\% & 0.02\% & 97.29\% \\ \hline \multirow{6}{*}{1990–2000} & a & 86.52\% & **5.74\%** & 4.69\% & 0.71\% & 2.88\% & 0.25\% \\  & b & **6.90\%** & 87.19\% & 5.06\% & 0.23\% & 0.17\% & 0.44\% \\  & c & 3.52\% & **5.08\%** & 85.88\% & 0.64\% & 0.12\% & 4.76\% \\  & d & **6.79\%** & 1.93\% & 4.34\% & 80.32\% & 0.61\% & 6.01\% \\  & e & **16.04\%** & 1.84\% & 1.73\% & 0.80\% & 79.37\% & 0.21\% \\  & f & 0.48\% & 0.63\% & **6.78\%** & 0.83\% & 0.04\% & 91.23\% \\ \hline \multirow{6}{*}{2000–2010} & a & 80.06\% & **9.13\%** & 6.17\% & 1.21\% & 3.17\% & 0.26\% \\  & b & **7.14\%** & 84.57\% & 7.10\% & 0.43\% & 0.51\% & 0.25\% \\  & c & 3.87\% & **5.43\%** & 86.89\% & 0.40\% & 0.20\% & 3.22\% \\  & d & **7.19\%** & 3.31\% & 4.27\% & 80.51\% & 1.85\% & 2.86\% \\  & e & **23.28\%** & 4.84\% & 2.57\% & 1.93\% & 67.07\% & 0.31\% \\  & f & 0.50\% & 0.28\% & **4.87\%** & 0.39\% & 0.08\% & 93.88\% \\ \hline \multirow{6}{*}{2010–2020} & a & 62.59\% & **16.32\%** & 9.51\% & 2.38\% & 8.04\% & 1.16\% \\  & b & **9.29\%** & 80.92\% & 6.26\% & 0.90\% & 1.17\% & 1.46\% \\  & c & 6.44\% & 10.30\% & 63.31\% & 1.86\% & 0.64\% & **17.45\%** \\  & d & **12.18\%** & 4.47\% & 5.64\% & 70.09\% & 3.55\% & 4.07\% \\  & e & **31.64\%** & 7.95\% & 4.53\% & 5.40\% & 49.43\% & 1.06\% \\  & f & 1.80\% & 1.53\% & **6.14\%** & 1.79\% & 0.29\% & 88.45\% \\ \hline \multirow{6}{*}{1980–2020} & a & 63.28\% & **15.33\%** & 12.18\% & 2.03\% & 4.52\% & 2.66\% \\  & b & **7.33\%** & 83.37\% & 6.97\% & 0.66\% & 0.40\% & 1.27\% \\ \cline{1-1}  & c & 5.87\% & 9.39\% & 71.16\% & 1.47\% & 0.24\% & **11.87\%** \\ \cline{1-1}  & d & **9.51\%** & 6.25\% & 4.43\% & 74.56\% & 2.02\% & 3.23\% \\ \cline{1-1}  & e & **16.81\%** & 8.88\% & 7.90\% & 3.15\% & 60.84\% & 2.43\% \\ \cline{1-1}  & f & 0.69\% & 1.32\% & **4.43\%** & 2.37\% & 0.07\% & 89.12\% \\ \hline \hline \end{tabular} Note: a—Cropland, b—forest, c—grassland, d—water, e—construction land, and f—unused land. Blue value indicates the percentage of land area that remained unchanged. Red value indicates the largest percentage of area for a given land use class that was transformed into another class.  
\end{table} 
Table 4: Land use transformation matrices (1980–2020). \begin{table}
\begin{tabular}{c c c c c c c c c c} \hline \hline  & \multicolumn{2}{c}{**Very Slight**} & \multicolumn{2}{c}{**Slight**} & \multicolumn{2}{c}{**Moderate**} & \multicolumn{2}{c}{**High**} & \multicolumn{2}{c}{**Severe**} \\ \cline{2-10}  & **S** & **P (\%)** & **S** & **P (\%)** & **S** & **P (\%)** & **S** & **P (\%)** & **S** & **P (\%)** \\ \hline
1980 & 404.60 & 42.60 & 325.01 & 34.22 & 115.02 & 12.11 & 104.10 & 10.96 & 13.78 & 1.45 \\
1990 & 404.81 & 42.6 land continued to expand significantly, while other land use classes decreased, with water experiencing the largest decline (\(-0.16\%\)). Between 2010 and 2020, construction land experienced its peak expansion (3.60%), while grassland continued to decline (\(-285\),600 km\({}^{2}\), \(-0.96\%\)). Cropland also decreased, but at a slower rate (\(-15\),000 km\({}^{2}\)), while forest and unused land expanded (0.08% and 0.98%, respectively). In summary, construction land has seen the most dramatic growth over the past 40 years, in contrast to the steady decline in grassland and water. Unused land expanded throughout the study period, except for a slight decrease during 2000-2010. The most rapid expansion occurred between 2010 and 2020. Cropland and forest land have maintained a relatively constant level.