From Land Use to Urban Expansion: A Comparative Study of Quanzhou and Xi’an in the East and West of China

Regional differences in land use transitions and urban expansion patterns have become increasingly pronounced under rapid urbanization. However, conventional land use and land cover change (LUCC) analyses often rely on independent graphical presentations, limiting systematic cross-regional comparison and the identification of spatial heterogeneity. To address this limitation, this study constructs a comparative land use transition analytical framework integrating LUCC contrastive transition patterns, the landscape expansion index (LEI), and the PLUS model. The framework enables structured identification of transition directions, intensity differentials, and stage-specific characteristics, thereby enhancing the reproducibility and comparability of cross-regional land use analysis. Using Xi’an (inland) and Quanzhou (coastal) as representative cases, this study analyzed their land use changes from 1990 to 2020 based on Intensity Analysis and LUCC contrastive transition patterns and quantified the differences in urban expansion using the urban expansion intensity index and expansion pattern metrics. The results show that the urban expansion of Xi’an and Quanzhou was active during 1990–2020, with crops as the main stable source of urban expansion. This urban expansion mainly took the form of edge-expansion and infilling, with urban development transitioning from disorderly expansion to intensive utilization. Notable regional disparities were observed: Forest conversion to urban land was substantially higher in Quanzhou, reflecting stronger ecological land pressure in coastal areas, whereas grass conversion to crops was more prominent in Xi’an, suggesting agricultural spatial adjustment under food security constraints in inland regions. The PLUS model further demonstrates that urban expansion is jointly influenced by topographic conditions (DEM) and economic growth (GDP), highlighting the coupled effects of natural constraints and development dynamics. This study clarifies the differentiation characteristics and driving forces of coastal and inland urban expansion, providing a scientific basis for differentiated territorial spatial planning, ecological protection, and farmland management in eastern and western regions. It also helps formulate more targeted urban development policies based on regional resource endowments, promoting regional coordination and sustainable urbanization.