How 2D/3D urban form shapes land surface temperature: a comparative analysis across four South Asian cities

Urban expansion has exacerbated the urban heat island (UHI) effect, endangering public health and urban ecosystems. While urban spatial morphology (USM) has a substantial influence on land surface temperature (LST), the varying effects across Global South cities remain poorly understood. This study investigates 2D/3D USM–LST relationships in the urban core areas of four South Asian cities using SDGSAT-1 high-resolution LST data and eleven USM metrics. Stepwise multiple linear regression is applied alongside XGBoost-SHAP interpretation to provide linear baseline comparisons and enhance interpretability. The building density (BD; Pearson's r = 0.60–0.71) and building volume (BV; r = 0.22–0.68) are significantly related to elevated LST, while vegetation volume (VV; r = −0.38 to −0.15) provides substantial cooling in all urban cores. Building volume has emerged as the dominant driver of increased LST in Karachi, Faisalabad, and Gujranwala, whereas building height is the primary factor in Lahore. For cooling effects, the pervious surface fraction is the key factor in all cities except Gujranwala, where the vegetation structure (volume and height) prevails. Furthermore, the relationship between the average building height and LST showed an inflection-like pattern in Karachi. These findings provide actionable insights for promoting heat-resilient urban planning through targeted morphological interventions.