Spatio-temporal distribution and influencing factors of tangible cultural heritage along the Grand Canal of China

The Grand Canal in China (GCC), representing a state-engineered linear water system at a national scale, is distinct from river systems formed through natural geomorphological and hydrological processes, having evolved into a distinctive heritage corridor through long-term transport organization, state governance, and cultural transmission. However, previous studies have largely been conducted at the level of administrative units or localized segments, focusing more on the attributes of individual heritage sites than on the corridor-scale continuity, temporality, and spatial-organizational functions of the GCC. Therefore, focusing on 918 nationally protected Tangible Cultural Heritage (TCH) sites located within cities along the GCC corridor, this study examines their spatiotemporal patterns and spatial associations with geographical and historical factors using the average nearest neighbor index, kernel density estimation, standard deviation ellipse, spatial overlay analysis, and historical document analysis. The results indicate that (1) The number of TCH sites exhibits a staged trajectory characterized by an initial decline, subsequent growth to a peak during the Ming and Qing dynasties, and a decline in the modern and contemporary period. (2) Spatially, a pattern characterized by “axis continuity, nodal clustering, and peripheral diffusion” has formed, with Beijing-Tianjin, Zhengzhou-Luoyang, and Suzhou-Hangzhou emerging as major concentration areas. (3) From a historical perspective, TCH follows a developmental path characterized by “midstream origin, north-south expansion, dual-core formation, and northward intensification”. (4) Natural geographical conditions show the strongest and most consistent association with the distribution of TCH, while historical and socio-cultural processes are associated with further differentiation and accumulation of TCH in core sections. The findings contribute to understanding the spatial evolution of linear heritage corridors and provide empirical evidence for integrated conservation planning of the GCC.