Slope characteristics of urban construction land and its correlation with ground slope in China

Abstract

Since the 21st century, China’s urban construction land has been growing rapidly, piquing academic interest. However, mountainous counties account for the majority in China, previous studies have concentrated on the horizontal expansion characteristics of construction land, leaving a gap in the vertical expansion. This study used datasets for urban construction land and digital elevation model to analyze the spatiotemporal evolution characteristics of construction land slope in 2670 China’s counties, by exploratory spatial data analysis. Furtherly, we explored the slope relationship between ground and construction land using regression analysis. The findings indicate what follows: (1) The average slope of construction land had a spatial pattern of “high in the south and low in the north,” with significant spatial agglomeration characteristics. And it had increased with the urban expansion, shifting the slope-weighted mean center toward the southeast while enhancing spatial agglomeration. (2) There was a significant and steadily rising linear association between the urban construction land slope and ground slope, due to spatial heterogeneity; the most affected counties were primarily located near the Sichuan basin. According to the results, we provided suggestions for the rational use and sustainable development of land in cities, especially for mountainous regions in a period of rapid urbanization.