The Urban Space Expansion Based On CA-Markov Model In Urumqi,Xinjiang

With the rapid expansion of urban space,some contradictions and problems that can not be ignored have surfaced,such as environmental pollution,abandoned farmland,traffic congestion and other "big city diseases".Therefore,exploring urbanization mode and planning urbanization process can effectively reduce the negative effects of urbanization,which is of great significance to promote the healthy and sustainable development of cities.Guided by the basic theories of geographic information system and remote sensing,I make full use of remote sensing data and statistical yearbook data to carry out the analysis of features and drivers of Urumqi's spatial expansion.First of all,I used remote sensing image to make the distribution map of the excavated land and analyzed the spatial expansion characteristics of Urumqi.Then,taking 2015 as the base period,I used CA Markov model to simulate and test the land distribution of Urumqi in 2018,and predicted the land distribution of Urumqi in 2025.Finally,the paper makes the principal component analysis and regression analysis of the driving factors of urban expansion in Urumqi with the statistical yearbook data from 2000 to 2017.Based on the above research,the main conclusions are as follows:(1)Since 2010,the construction area has expanded rapidly,with an average annual expansion of 16.9 square kilometers from 2010 to 2015,and an average annual expansion of 27.53 square kilometers from 2015 to 2018.The cultivated land area continued to decrease,among which the decrease rate was faster from 2010 to 2015,and slower from 2015 to 2018.The area of forest land continues to decrease,especially from 2015 to 2018.The actual construction area of Midong District accounts for a small proportion of the total area of the District,and it is the area with the lowest land use rate except Daban city and Urumqi county.The cultivated land area of Toutunhe District continued to decrease.Shuimogou District and the new urban area have a large proportion of construction land,a high land use rate and a small potential for spatial expansion.Especially in the new urban area,cultivated land and urban construction land account for more than 99% of the area,so the way of spatial expansion in the new urban area is relatively single,that is to say,expropriation of cultivated land.The cultivated land area of Tianshan District has hardly changed,and the change of construction land is also very small.(2)From the analysis of the three indexes of urban spatial expansion speed,expansion rate and expansion intensity,it can be concluded that Urumqi is a high-speed expansion type from the perspective of expansion speed,a medium speed expansion type from the perspective of expansion rate,and a low-speed expansion type from the perspective of expansion intensity.(3)Using the parameters of probability transfer matrix of land use area from 2010 to 2015,the distribution of land use in 2018 is simulated by Ca Markov model based on 2015.The accuracy test of the model shows that the reliability of the model is high.Except for water,the relative errors of other types of land use simulation are less than 10.14%.According to the model,the cultivated land area of Urumqi in 2025 will be 977.92 square kilometers,the forest land area will be 445.66 square kilometers,the grassland area will be 6773.65 square kilometers,the water area will be 507.13 square kilometers,and the construction land area will be 1827.85 square kilometers Shore.The expansion speed in the south of the main urban area is relatively slow,and the construction land in the north grows more and more with time.The part of the western area that basically expands to connect with the urban area of Changji City is getting larger and larger,which basically conforms to the control principle of "South control,North expansion,first West extension,and then east advancement" in Urumqi urban planning in 2011-2020.(4)Principal component analysis only extracts the first principal component,with a contribution rate of 95.610%.The first principal component is closely related to population,economy,transportation,energy consumption and municipal construction.Among these driving factors,the urban spatial expansion of Urumqi is greatly affected by population,economy,transportation and municipal construction in a short period of time,but less by scientific research.Based on the above conclusions,it is suggested that Urumqi city should protect the natural environment and save water resources while maintaining the urban construction land needed for development and ensuring the urban economic growth.Reasonably control the development speed,do a good job in the transformation of the old urban area,explore the tourism resources of surrounding districts and counties,and do a good job in municipal construction and traffic construction.In addition,we should pay attention to scientific research and innovation,so that scientific and technological progress can drive economic development,so as to promote urban development.