Temporal, Spatial Distribution Characteristics, and Influencing Factors of National Key Cultural Relics Protection Units in the Yangtze River Delta

It is of great significance to study the spatial and temporal distribution characteristics and influencing factors of national key cultural relics protection units in the Yangtze River Delta region. Taking the national key cultural relics protection units in the Yangtze River Delta as an example, the spatial and temporal distribution characteristics and influencing factors of the sites were studied by using the methods of nearest proximity index, spatial density, standard deviation ellipse, and geographic detector. It can be concluded that the number of key cultural relics under protection in the Yangtze River Delta region is concentrated in the Song, Yuan, Ming and Qing Dynasties and since modern times, with the main types of ancient buildings, and the largest number in the 100-year time scale since modern times. On the whole, the spatial density of the national insurance unit has formed contiguous areas dominated by “Shanghai, Suzhou, and Wuxi,†“Nanjing, Yangzhou,†“Hangzhou and Shaoxing†and single core areas dominated by Ningbo and Huangshan, with the spatial distribution characteristics of “three contiguous areas and two single cores.†During the eight periods from prehistoric period to modern times, the national security units showed a state of agglomeration in spatial distribution, showing the transfer trend of “Southwest-northwest-southeast-southeast-southeast-northwest-northeast†and the evolution process of “agglomeration—dispersion—agglomeration—dispersion—agglomeration—agglomeration.†Natural environmental factors such as altitude and river network density, and socio-economic factors such as economic development level, abundance of scenic spots, abundance of intangible cultural heritage resources and total population have a significant impact on the spatial distribution of national protection units in the Yangtze River Delta.