# Analysing Land Cover Change in the Valencian Community through Landsat Imagery: From 1984 to 2022
## 3 Results
### Land Cover Temporal Analysis
\begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Class** & **1985** & **1990** & **1995** & **2000** & **2005** & **2010** & **2015** & **2020** \\ \hline
**Water bodies** & 87.82 & 116.61 & 82.13 & 88.06 & 87.38 & 111.98 & 125.19 & 116.70 \\
**Built-up Areas** & 484.24 & 702.85 & 759.72 & 788.41 & 849.70 & 857.32 & 869.84 & 908.57 \\
**Dense Veg.** & 11,212.25 & 14,060.05 & 10,460.70 & 13,150.16 & 12,159.99 & 13,934.87 & 12,631.18 & 14,437.68 \\
**Sparse Veg.** & 11,324.52 & 8237.74 & 11,780.41 & 9159.91 & 10,038.23 & 8318.86 & 957.46 & 7762.19 \\
**Other** & 146.59 & 138.36 & 171.92 & 68.85 & 120.02 & 32.59 & 57.81 & 30.70 \\ \hline \hline \end{tabular}
\end{table} 
Table 3: Area (km\({}^{2}\)) of each class obtained with the Random Forest algorithm, calculated every 5 years using Landsat 5–8 images for the period 1985–2020. \begin{table}
\begin{tabular}{c c c c c c c c c} \hline \hline
**Class** & **1985** & **1990** & **1995** & **2000** & **2005** & **2010** & **2015** & **2020** \\ \hline
**Water bodies** & 0.38 & 0.50 & 0.35 & 0.38 & 0.38 & 0.48 & 0.54 & 0.50 \\
**Built-up Areas** & 2.08 & 3.02 & 3.27 & 3.39 & 3.65 & 3.69 & 3.74 & 3.91 \\
**Dense Veg.** & 48.21 & 60.46 & 44.98 & 56.55 & 52.29 & 59.92 & 54.31 & 62.08 \\
**Sparse Veg.** & 48.70 & 35.42 & 50.66 & 39.39 & 43.17 & 35.77 & 41.16 & 33.38 \\
**Other** & 0.63 & 0.59 & 0.74 & 0.30 & 0.52 & 0.14 & 0.25 & 0.13 \\ \hline \hline \end{tabular}
\end{table} 
Table 4: Area (%, referring to the total area of the Valencian Community) of each class obtained with the Random Forest algorithm, calculated every 5 years using Landsat 5–8 images, for the period 1985–2020. Figure 7: Graph illustrating the percentage distribution of land cover classes in the Valencian Community. The calculations were performed every 5 years using Landsat 5–8 images, covering the period from 1985 to 2020. Subsequently, linear and polynomial adjustments were employed to examine trends for each class from 1984 to 2022. The consistent growth in the Built-up Areas class and the simultaneous decline in the combined Dense and Sparse Vegetation classes reveal a positive trend indicative of urban expansion in the community. Conversely, a negative trend signals an overall reduction in vegetation (Figure 9). In both cases, polynomial regression yields the best fit (R\({}^{2}\) of 0.95 and 0.84 for Built-up Areas and Sparse + Dense Vegetation, respectively). The 'Water bodies' class shows no clear trend, maintaining oscillations between similar values throughout the period. Figure 8: Graph illustrating the overall percentage distribution of land cover classes in the Valencian Community. The calculations were performed every 5 years using Landsat 5–8 images, covering the period from 1985 to 2020. Figure 9: Polynomial regression performed in the Built-up Areas class (**top left**), Dense + Sparse Vegetation (**top right**), Water Bodies (**bottom left**), and Other (**bottom right**), spanning the period from 1984 to 2022. A separate analysis of both Dense and Sparse Vegetation classes reveals consistent fluctuations over the years. Some years, such as 1990 (60.46%) and 2020 (62.08%), show high percentages of Dense Vegetation, while others, including 1985, 1995, and 2005, show lower percentages (48.21%, 44.98%, and 54.31%, respectively). Concerning the 'Other' class, it manifests a negative trend (R\({}^{2}\) of 0.78). In Figure 10, a superimposition of the Built-up Areas classes for all years, each represented by a distinct colour, facilitates the observation of urban growth in the cities of Valencia, Alicante, and Castellon throughout the study interval. We can observe that the most significant urbanisation impact occurred from 1985 to 1990, as previously discussed. Additionally, the introduction of ports in 2005 (absent in 2000) and their subsequent expansions in 2010, 2015, and 2020 are discernible.