Spatial Temporal Analysis of Impervious Surface Distribution at the Neighborhood Scale in the Urban Center: The Case of Ordu-Altınordu (Türkiye)

Background/Aim: The increasing replacement of natural surfaces with impervious surfaces due to rapid urbanization has significant spatial and environmental impacts on urban ecosystems. Therefore, monitoring the spatial distribution and temporal change of impervious surfaces is essential for understanding urban growth processes and supporting sustainable planning decisions. This study aimed to analyze the spatial distribution of impervious surfaces and their changes between 2015 and 2025 in 18 neighborhoods of Altınordu district (Ordu, Türkiye) using the Enhanced Normalized Difference Impervious Surface Index (ENDISI).Methods: Sentinel-2 Level-2A satellite imagery acquired for 2015 and 2025 was used to calculate the ENDISI. Impervious surfaces were extracted using a threshold-based classification approach after preprocessing and water masking with the Modified Normalized Difference Water Index (MNDWI). Classification performance was evaluated using the Spectral Discrimination Index (SDI) and an error matrix-based accuracy assessment. In addition, neighborhood-level impervious surface proportions for 2015 and 2025 were statistically compared using the Wilcoxon signed-rank test.Results: The results revealed an overall increase in impervious surface areas between 2015 and 2025. Neighborhood-scale analyses demonstrated that impervious surface change was spatially heterogeneous, with the magnitude of change varying considerably among the selected neighborhoods. The paired comparison confirmed a statistically significant difference in neighborhood-level impervious surface proportions between 2015 and 2025 (p = 0.004), with a large effect size (r_rb = 0.84). The classification achieved overall accuracies of 92.3% and 94.3%, with Kappa coefficients of 0.84 and 0.88 for 2015 and 2025, respectively.Conclusion: The findings indicate that ENDISI provided satisfactory classification performance within the selected urban neighborhoods of Altınordu. The study offers a case-specific neighborhood-scale assessment of net impervious-surface change that can contribute to local urban monitoring and spatial planning evaluations.