Abstract:
In this paper, Nairobi, Kenya is used as the research area. The calibrated SLEUTH model is used to effectively monitor, simulate and analyze the growth momentum and direction of Nairobi's urban spatiotemporal growth pattern. The parameters obtained by the model are: growth coefficient is 1; reproduction coefficient, 1; spreading coefficient, 76; slope impedance, 75; and road gravitation, 69. Meanwhile, the goodness-of-fit of the three calibration steps is above 0.5, which meets the requirements of accuracy. The SLEUTH urban expansion simulation shows that Nairobi will experience a fast urban expansion phase from 2020 to 2035, with an average annual growth rate of over 5%; and that the urban expansion rate will decrease between 2035 and 2050 until it stabilizes. It is predicted that by 2050, the urban area will have occupied about 60% of the total county area. From a spatial perspective, Nairobi's future expansion will extend in its northwest and southeast. Judging from the factors affecting the expansion, Nairobi's expansion is closely related to the construction of transportation facilities, topography and the distribution of original land use. Among the three influencing factors, road gravity is the greatest. Expansion areas are mainly concentrated around first-grade highways and railway stations, and in areas with flat slopes. Cultivated land and grassland acquired through land use will take up the largest proportion of land to be used in the city's future expansion,