Spatiotemporal Distribution and Influencing Factors of Modern Historic Buildings in Kaiyuan Ancient City Based on a GIS Database

Rapid urbanization and shifting modern transportation technologies have exposed traditional ancient cities to passive marginalization, heritage loss, and spatial fragmentation. Yet the long-term spatial succession patterns and micro-scale decline factors of their unlisted built heritage remain insufficiently quantified. Focusing on 347 modern historic buildings (1840–1949) in Kaiyuan Ancient City, China—historically a capital of four states and a key military stronghold across five dynasties—this study built a four-level GIS database integrating multi-period historical maps, terrain and pre-demolition surveyed basemaps, archival literature, and field surveys to investigate their spatiotemporal evolution, micro-spatial pathology, and non-stationary influencing factors. We constructed a multidimensional "Point–Line–Polygon–Volume" geospatial analytical framework that integrates Average Nearest Neighbor (ANN), Kernel Density Estimation (KDE), Standard Deviational Ellipse (SDE), Space Syntax, Spatial Autocorrelation, and Spatial Regression models. The results show a pronounced northwest–southeast clustering pattern of historic buildings. Rather than expanding outward like modern cities, the ancient city underwent unidirectional centripetal contraction and a southward centroid shift, with peripheral military–political lands converted to agricultural use and residential areas densified in the core, while at the micro-spatial scale grassroots property rights fragmentation doubled the proportion of dead-end streets within blocks, caused topological polarization along main arterial roads, and accompanied the physical compression of original courtyard green spaces by informal infill development. Structural reversal occurred in the influencing factors of spatial heterogeneity over the study period according to Geographically Weighted Regression (GWR). Early settlement patterns were primarily shaped by natural baseline constraints of topography and historical water systems that initially provided a flood-safe foundation and fostered water-oriented clustering before obstructing internal traffic; over time, socioeconomic factors dominated by railway capital deprivation and the outward relocation of the administrative center became the primary influencing forces, which pulled commercial spaces southward, filled central official plots with new construction, and preserved the traditional residential pattern in the northwest as public facilities acted as spatial anchors during turbulent periods through their shelter and relief functions. Targeted conservation strategies informed by these diagnostics combine road network unblocking and ecological restoration, differentiated zoning control and peripheral land utilization, and facility adaptive conversion and digital reproduction, clarifying the spatial patterns and evolutionary influencing factors of built heritage in marginalized historic towns while showing how multidimensional GIS quantitative analysis supports evidence-based micro-regeneration and classified dynamic revitalization for unlisted built heritage.