# Utilizing Sentinel-2 Satellite Imagery for LULC and NDVI Change Dynamics for Celephu, Bhutan
## 3 Results and Discussions
### LULC Statistics  
The LULC statistics for Gelephu are presented in Table 1. In 2016 the area covered by vegetation was 44.31 km\({}^{2}\) making up 81.30% of the total area. However, by 2023 the vegetation area had shrunk to 37.62 km\({}^{2}\), which represents a decrease of, about 11.99%. This means that the percentage of land covered by vegetation in relation to the area dropped to around 69.31%. As for the water area in 2016, it accounted for 0.52 km\({}^{2}\) or about 0.95% of the total area due to being occupied by a river. However, in 2023 this water area decreased significantly to about 0.02 km\({}^{2}\) indicating a decline of roughly 0.91%. This change can be attributed to alterations in the watercourse itself. Consequently, the proportion of water coverage in the area decreased to approximately just, 0.04%. The built-up area in 2016 was 4.03 km\({}^{2}\), representing 7.39% of the total area. By 2023, the built-up area increased to 7.08 km\({}^{2}\), showing a significant increase of 5.65%. The portion of the built-up area in the total area increased to 13.04%. Likewise, the barren land coverage was 5.64 km\({}^{2}\) in 2016, accounting for 10.35% of the total area. The barren land area increased to 9.55 km\({}^{2}\) in 2023, representing a significant increase of 7.25%. The proportion of barren land in the total area increased to 17.60%. Overall, between 2016 and 2023, vegetation and water cover decreased while built-up areas and barren land increased significantly.  
\begin{table}
\begin{tabular}{c c c c c c c c c c c} \hline \hline \multirow{2}{*}{**Class**} & \multicolumn{4}{c}{**Gelephu**} & \multicolumn{4}{c}{**Gelephu Thromde**} \\ \cline{2-10}  & \multicolumn{2}{c}{**Area (km\({}^{2}\))**} & \multicolumn{2}{c}{**\% Coverage**} & \multirow{2}{*}{**\%**} & \multirow{2}{*}{**Area (km\({}^{2}\))**} & \multirow{2}{*}{**\% Coverage**} & \multirow{2}{*}{**\%**} & \multirow{2}{*}{**\% Coverage**} & \multirow{2}{*}{**\%**} \\ \cline{2-10}  & **2016** & **2023** & **2016** & **2023** & & & & **2016** & **2023** & **2016** & **2023** & **Change** \\ \hline Vegetation & 44.31 & 37.62 & 81.30 & 69.31 & \(-\)11.99 & 7.15 & 3.96 & 67.04 & 37.11 & \(-\)29.93 \\ \hline Water & 0.52 & 0.02 & 0.95 & 0.04 & \(-\)0.91 & 0.03 & 0.04 & 0.25 & 0.37 & 0.12 \\ \hline Built-up area & 4.03 & 7.08 & 7.39 & 13.04 & 5.65 & 1.73 & 3.34 & 16.24 & 31.28 & 15.05 \\ \hline Barren land & 5.64 & 9.55 & 10.35 & 17.60 & 7.25 & 1.76 & 3.33 & 16.47 & 31.23 & 14.76 \\ \hline Total & 54.50 & 54.27 & 100.00 & 100.00 & & 10.66 & 10.66 & 100.00 & 100.00 & \\ \hline \hline \end{tabular}
\end{table}
Table 1: Summary of LULC statistics for Gelephu and Gelephu Thromde respectively.  
Figure 7: LULC transition pattern for Gelephu. The colors represent the land class color scheme used for LULC mapping (Green: Vegetation; Blue: Water; Red: Built-up; Yellow: Barren land).  
Additionally, Table 1 lists the LULC statistics for Gelephu Thromde. The LULC statistics between 2016 and 2023 show significant transformations in Thromde's land use dynamics. Vegetation, which accounted for 67.04% of the total area in 2016, saw a significant decrease of 29.93%. The vegetation area decreased from 7.15 to 3.96 km\({}^{2}\), with a corresponding decrease in percentage cover from 67.04% to 37.11%. While water is a smaller land cover category, it saw a slight increase in both absolute area and percentage coverage. The water area increased from 0.03 to 0.04 km\({}^{2}\) with a corresponding increase in percentage cover from 0.25% to 0.37%. On the other hand, both the built-up area and the undeveloped land showed significant growth during the period under study. The built-up area increased by 15.05%, from 1.73 to 3.34 km\({}^{2}\), with the percent coverage rising from 16.24% to 31.28%, indicating rapid urbanization. Similarly, the area of barren land increased by 14.76%, from 1.76 to 3.33 km\({}^{2}\), with the percent coverage increasing from 16.47% to 31.23%.