Multi-scale analysis of the spatial structure of China's major function zoning

The spatial structures of China's Major Function Zoning are important constraining indicators in all types of spatial planning and key parameters for accurately downscaling major functions. Taking the proportion of urbanization zones, agricultural development zones and ecological security zones as the basic parameter, this paper explores the spatial structures of major function zoning at different scales using spatial statistics, spatial modeling and landscape metrics methods. The results show: First, major function zones have spatial gradient structures, which are prominently represented by latitudinal and longitudinal gradients, a coastal distance gradient, and an eastern-central-western gradient. Second, the pole-axis system structure and core-periphery structure exist at provincial scales. The general principle of the pole-axis structure is that as one moves along the distance axis, the proportion of urbanization zones decreases and the proportion of ecological security zones increases. This also means that the proportion of different function zones has a ring-shaped spatial differentiation principle with distance from the core. Third, there is a spatial mosaic structure at the city and county scale. This spatial mosaic structure has features of both spatial heterogeneity, such as agglomeration and dispersion, as well as of mutual, adjacent topological correlation and spatial proximity. The results of this study contribute to scientific knowledge on major function zones and the principles of spatial organization, and it acts as an important reference for China's integrated geographical zoning.