[Simulation of Lanzhou urban land expansion based on multi-agent model]

Using the four periods of land use data and socio-economic statistics of Lanzhou City in 1995, 2005, 2015 and 2018, we examined the evolution characteristics and driving forces of urban land use in Lanzhou, with expansion intensity index, Logistic regression, and principal component analysis method. Based on the multi-agent model, the expansion of urban land use in Lanzhou under multiple scenarios in 2025 was simulated using Netlogo software. The results showed that the intensity and scale of urban land expansion in Lanzhou City from 1995 to 2018 showed an increasing trend, with a total of 307 km² of cultivated land and water area. The expansion of urban land in Lanzhou City was significantly related to regional GDP, social fixed asset investment, population density, population, policy, and terrain. The multi-agent model on the Netlogo software could simulate the expansion trend of urban land in Lanzhou, which provided a reliable simulation method for the expansion of valley-type cities. From 2020 to 2025, urban land use under the comprehensive development scenario, natural expansion development scenario, ecological and farmland protection development scenario all showed an increasing trend. The scale of expansion would range between 42.6-134.3 km². The expansion mode would mainly be infilled expansion. Our results could provide decision support for the land space planning and ecological environment layout optimization for Lanzhou City.