Spatial Delimitation of Urban-Rural Fringe Based on POI and Nighttime Light Data： A Case Study of Wuhan City

Objectives The identification of urban-rural fringe boundaries is a fundamental task for fine urban and rural planning and governance, and it plays a vital role in promoting sustainable land use and urban-rural integration. The traditional methods for delineating urban-rural boundaries have many limitations, such as reliance on single data sources, difficulty in data acquisition, and low temporal and spatial resolution.

Methods This paper proposes a novel method for identifying urban-rural fringe boundaries, based on the fusion of points of interest (POI) from electronic map and nighttime light data of national polar-orbiting partnership (NPP) satellite, in conjunction with the spatial structure of urban and rural space. Taking Wuhan City as a case study, this paper employs break point analysis to identify spatial mutation points and determine urban-rural fringe boundaries. The results are validated and compared using land use structure entropy, normalized difference vegetation index, and population density data, with field verification conducted in selected typical areas.

Results The results show that by considering differences in facility types, light intensity, and resolution in POI and nighttime light data, the NPP &POI composite index for boundary delineation offers higher accuracy and timeliness compared to the boundaries identified using POI, nighttime light, and population density data individually. NPP &POI data can more effectively reflect the vitality of urban-rural development compared to land use and landscape data. The quantitative identification of potential central areas and multi-layered structures in urban-rural settings is significant for research on urban-rural infrastructure allocation, industrial division, and ecological function distribution.

Conclusions The secondary mutation pattern of NPP &POI data in urban-rural spaces confirms the objective existence of urban-rural fringe areas as territorial entities emerging from urban expansion, providing empirical support for the urban-rural triad structure theory.