Research on Use Regulation of Areas Adjacent to the Urban Development Boundary Based on Markov-PLUS Coupled Model: A Case Study of Xichang Central Urban Area

Areas adjacent to the urban development boundary (UDB) are significantly influenced by both urban center diffusion and rural agglomeration. Currently, UDB delineation in many Chinese cities lacks flexibility and fails to meet actual development needs, necessitating multi-source data fusion and quantitative simulation to guide territorial space use regulation. This study focuses on the adjacent areas of the Xichang central urban area, exploring a dual-line guided control mode combined with policy orientations on incremental space scales. By coupling the Markov-PLUS model, we construct a comprehensive technical route encompassing research scope determination, spatial evolution analysis, scenario prediction, and the delineation of urban-rural coordination zones. The results demonstrate that urban spatial morphology changes in Xichang are characterized by dominant boundary advances and local cluster growth. Key driving factors include terrain elevation, population density, road proximity, and economic output, which align with the spatial growth logic of mountainous river valley cities. Furthermore, integrating the Markov model with the CARS module predicts the central urban space scale to reach 99.2 square kilometers, with the coordination zone spanning 11.75 square kilometers. Ultimately, the Markov-PLUS coupled model effectively reflects the driving mechanisms of urban spatial evolution and accurately simulates development trajectories. This research provides a robust methodological foundation for future predictive studies and offers critical insights for optimizing territorial space use regulation in similar urban environments.