Multi-Scale Gradient Patterns of Building Morphology in Town Peripheries and Their Association with Economic Development: A Case Study of 13 Prefecture-Level Cities in Jiangsu Province, China

This study examined the building morphology of 1491 town-level administrative units across 13 prefecture-level cities in Jiangsu Province, China, within inner-boundary belts of 50, 100, 150, and 200 m. Four indicators including mean building spacing, mean building height, mean building volume, and mean building shape index were calculated, and their gradients, correlations, economic associations, and inter-town similarity networks were analyzed. Northern Jiangsu exhibits greater within-city variation in peripheral building morphology than Southern Jiangsu. With increasing belt width, building volume increased and spacing decreased; while height and shape index showed no consistent monotonic trends across all cities. Mean spacing was negatively correlated with height, volume, and shape index, whereas height, volume, and shape index are positively interrelated. In higher per-capita GDP cities, the negative correlation between spacing and shape index and the positive correlation between height and shape index were more pronounced, although this finding is exploratory given the 13-city sample. Similarity network analysis reveals clear clustering by prefecture-level city, with within-city similarity significantly higher than between-city similarity across all belt widths. Similarity ranking remained consistent across belt widths, although some local restructuring occurs between the immediate boundary zone and interior. These findings contribute to urban morphology research and planning policy.