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Arid Land Geography ›› 2021, Vol. 44 ›› Issue (6): 1729-1739.doi: 10.12118/j.issn.1000–6060.2021.06.21

• Earth Information Sciences • Previous Articles     Next Articles

Quantitative analysis of urban expansion and response factors in Urumqi City based on random forest algorithm and geographical detector

ZHAO Yongyu1(),Alimujiang KASIM1,2(),GAO Pengwen1,LIANG Hongwu1   

  1. 1. School of Geographic Science and Tourism, Xinjiang Normal University, Urumqi 830054, Xinjiang, China
    2. Research Center for Urbanization Development of Silk Road Economic Belt, Xinjiang Normal University, Urumqi 830054, Xinjiang, China
  • Received:2020-11-25 Revised:2021-03-23 Online:2021-11-25 Published:2021-12-03
  • Contact: KASIM Alimujiang E-mail:zyy971226@163.com;alimkasim@xjnu.edu.cn

Abstract:

In this paper, taking Urumqi City in northwest China as an example, the spatial land cover/land use (LUCC) characteristics of Urumqi from 2000 to 2020 were analyzed on the basis of the thematic mapper (TM) and oil remote sensing image data from three phases of Landsat in 2000, 2010, and 2020. This was achieved using the random forest classification method based on a 250 m×250 m grid cell. The underlying factors were further revealed using a geographic detector model, and a quantitative analysis and an evaluation of Urumqi City from 2000 to 2020 were carried out to determine the spatial and temporal changes and response factors of LUCC over the past 20 years. The results demonstrated the following: (1) Over the past 20 years, Urumqi has been rapidly urbanized, and the land area dedicated to construction has greatly increased. On the basis of the built-up area in 2000, Urumqi has been developing to the north, northeast, northwest, and southeast, mainly in the outward expansion mode, although urban interior filling-type growth also exhibits a trend of intensive growth. (2) Over the past 20 years, the green space in Urumqi City has fluctuated to a certain extent, although there has been an increasing trend overall. At the same time, the amount of bare land has shown a trend of continuous decrease. (3) The main influencing the temporal and spatial variation of LUCC in Urumqi City were identified using a geographical detector, and the results revealed that the dominant factor with the highest contribution rate was normalized difference vegetation index (NDVI). According to the interactive factor detection results, when NDVI and digital elevation model were used together, the two enhanced each other, and the explanatory power was the greatest.

Key words: land use, random forest algorithm, grid cell, geographical detector, Urumqi City