Research on the Characteristic Identification and Multidimensional Dynamic Evolution of Urban–Rural Fringe in Harbin, China

The urban–rural fringe, serving as a frontier space and protective barrier for urban–rural factor circulation, is a complex area marked by significant human–land conflicts. Therefore, scientifically identifying and dynamically monitoring the urban–rural fringe is crucial for its integrated development and spatial governance. In this context, this paper constructs an information entropy model using land use data, combined with the central gravitational agglomeration method, to accurately identify the evolution of Harbin’s urban–rural fringe over the past 40 years. The research reveals that Harbin’s urban–rural fringe exhibits a distinct circling pattern, with spatial morphology changes characterized as “low-speed spreading—jumping expansion—internal dissimilarity”, allowing for improved identification of its three types: stable, expanding, and degrading. The study also tracks the scale of the urban–rural fringe in Harbin with three types of stable, expanding, and degrading urban–rural fringe. Drawing on previous research, we visualize the fringe area’s functional spatial positioning, showing its dominant function shifting from a production–ecological composite to a production–life–ecological coordinated function. Concurrently, the study’s findings, alongside Harbin’s socioeconomic development, indicate that the urban–rural fringe’s evolution is driven by economic, policy, and environmental factors. Based on the multi-dimensional research outcomes, we conclude that the evolution of Harbin’s urban–rural fringe can be divided into three stages: a slow gestation period (1980–1990), a rapid development period (1990–2010), and a stable reconstruction phase (2010–2020). In the initial phase, urban and rural development is minimal; during the second phase, the trend of urban expansion is significant, and the urban–rural fringe is rapidly shifted to the city; and in the latter stage, urban and rural elements are stabilized and coordinated, and urban and rural areas are realized to be developed and reconstructed as one. This paper provides a scientific basis for understanding the dynamic evolution of the urban–rural fringe in Harbin City and is an important reference for future territorial spatial planning and development.