Mapping heat vulnerability in Esenler, Istanbul using equal and entropy weighting: A multi-dimensional GIS approach

Urban heat vulnerability is an emerging challenge for rapidly densifying cities, where socio-economic inequalities intersect with physical exposure. This study assesses neighborhood-level heat vulnerability in Esenler District, Istanbul, by integrating environmental and socio-demographic indicators within a composite Heat Vulnerability Index (HVI). Using satellite-derived indicators, including Land Surface Temperature (LST), Normalized Difference Vegetation Index (NDVI), and Normalized Difference Built-up Index (NDBI), combined with socio-economic and adaptive capacity measures, the analysis applies both Equal Weighting and Entropy Weighting Methods to evaluate spatial variability and methodological robustness. Results reveal significant intra-district disparities, with HVI values ranging from 0.15 to 0.69 (Δ = 0.54). The majority of neighborhoods (15 of 17) fall within the high-vulnerability category, representing approximately 96% of the population, while only one neighborhood exhibits low vulnerability and one shows moderate vulnerability. The strong correlation (r = 0.94) between Equal and Entropy-weighted results confirms the index’s methodological stability. Spatial clustering of high vulnerability in central Esenler underscores how dense urban morphology and social disadvantage co-produce climatic risk. This study addresses a critical gap in Istanbul’s urban climate literature by providing one of the first data-driven, neighborhood-scale HVI applications. A Heat Vulnerability–Adaptive Capacity matrix translates results into a neighborhood-level prioritization scheme, identifying critical hotspots (N3, N7, N10) for immediate adaptation. Integrating entropy-based weighting enhances the interpretation of diverse environmental and social datasets, offering a replicable model for other contexts. The results emphasize targeted adaptation measures such as expanding green infrastructure, improving thermal comfort, and prioritizing vulnerable communities.

Keywords: Heat Vulnerability Index (HVI), urban heat exposure, entropy weighting method, esenler district, spatial analysis, climate adaptation.