Evaluation of intensive urban land use and analysis of obstacle factors in northern slope of Tianshan mountains

Land is the spatial carrier of a city’s society, economy and ecosystem. Intensive urban land use is an important means to improve land use efficiency, which is of great significance for optimizing the allocation of urban land resources and promoting the coordinated development of urban society, economy and ecology. In this manuscript, considering the regional characteristics, economic status and land use characteristics of the four cities (i.e. Urumqi, Karamay, Shihezi, and Changji) in the northern slope of the Tianshan Mountains, we selected 16 indicators from three aspects of economic-society-ecological factors to establish an evaluation index system for intensive land use. In order to compare the intensive degrees between four cities, a global standardized data table (X' ij)16×9×4 was established by a multivariate standardization method, based on the original data of four cities' evaluation indicators, which provide a unified data base for the intensive use of land in the four cities on the northern slope of the Tianshan Mountains. In addition, the optimal combination weighting method was employed to assign weights for four cities' evaluation indicators, respectively, which was the integration of subjective weighting (AHP) and objective weighting (Entropy weighting method) via the Lagrange multiplier method. This approach of weighting gives consideration to the subjective and objective factors of the studied area and more accurately reflects the locational differences of different cities. On this basis, multi-factor comprehensive evaluation was taken to calculate the intensive degrees of four cities, and to evaluate the status of land intensive by the four-level evaluation criteria, i.e. highly intensive, moderately intensive, marginally intensive, and not intensive. Moreover, a coordination model based on benefit theory and balance theory, and an obstacle model were introduced to analyze the coherence and obstacle factors, respectively, and to explore the main obstacles that affected urban land intensive, aiming to provide guidance for the development of intensive urban land use. Our findings revealed that: (1) The intensity of land use in the four cities showed an overall upward trend from 2008 to 2016, the mean value of intensity were in the order of Karamay City (0.562) > Shihezi City (0.532) > Changji City (0.512) > Urumqi City (0.476). There was still much room for improvement in the marginal-intensive land use (III). (2) The degree of land intensity and coordination had a strong correlation with a consistent evolution trend generally. According to the average degree of internal coordination, rankings were Karamay City (0.594) > Changji City (0.591) > Shihezi City (0.502) > Urumqi City (0.466). (3) From the perspective of obstacles, the status of obstacles in the four cities varied, but the overall performance was economic obstacle > social obstacle > ecological obstacle, and the degree of ecological obstacle continued to decrease. There were certain regional differences in various obstacle factors affecting urban land intensive, but the GDP-based economic indicators and population-based social indicators were the main obstacles overall. The results indicated that the assessment of land intensive use based on the optimal combination weighting method not only guaranteed the unity of comparison, but also reflected the difference in location, thus achieving an in-depth analysis of the factors affecting obstacle degree and the evolution of urban land intensive use accurately and effectively.