Research On Land Use Change And Simulation In Gannan County Based On GF Data

In the research on land,research on land use change has become a research hotspot,and the construction of land use change simulation model is the key research content of land use.In this paper,Gannan County of Qiqihar City is used as the research area.The main data sources are selected from the three remote sensing images of Gannan County in 2010(Landsat),2014(GF)and 2018(GF).The auxiliary data are selected from DEM data,boundary vector data and other socio-economic data,based on ENVI and ArcGIS.And IDRISI software,through the land use transfer matrix,spatial dynamics,land use degree and other models to analyze the changes and evolution of land use spatial pattern in Gannan County during the 8 years,and construct the CA-Markov model to study the spatial pattern of land use in the study area in 2018 After forecasting and verifying the model simulation accuracy,the land use pattern of 2022 is simulated and analyzed to provide technical support and theoretical basis for the rationality and sustainability of future land use in Gannan County.The results show:(1)In 2010,cultivated land was the most important type of land use in the study area,accounting for 83.23% of the total area.The grassland area is second to the cultivated land,accounting for 5.69%.In 2010-2018,the land use pattern of Gannan County showed that the area of cultivated land continued to decline,and the area of forest land,grassland,residential land and water area continued to expand,and the area of unused land increased first and then decreased.The cultivated land changed the most,and the area decreased by 710 km2.The expansion trend of forest land and grassland is obvious,and the area has increased by 235.38km2 and 214.67km2 respectively.(2)From the land use type transfer matrix of 2010~2014 and 2014~2018,the retention rate of cultivated land is 81.06% and 81.46%,respectively.Resident construction land retention rates were 64.84% and 65.61%,respectively.The retention rate of forest land is low,44.20% and 46.87% respectively.The grassland retention rates were 52.69% and 46.39%,respectively.Water and unused land have the lowest retention rates.The conversion of cultivated land to other land types is the main reason for the decline in cultivated land area and the increase in other land types.(3)Based on CA-Markov model to simulate the spatial pattern of land use in 2022,the simulation results show that the proportion of cultivated land,forest land,grassland,residential land,water area and unused land is 54.02%,14.28%,14.58%,respectively.8.42%,7.42% and 1.29%.Compared with 2018,except for the shrinkage of cultivated land,other land types are expanding.(4)Through research on the driving mechanism of land use spatial pattern change in the study area,it is known that the cultivated land,residential building land and water area are suitable to be concentrated between 0-2° slope.The woodland is suitable to be concentrated in the slope of 15-25°,and there is also a high distribution between the slopes of 25-65°.Economic development is the main reason for the expansion of residential land and the decline of cultivated land.The increase in precipitation is an important factor in the expansion of water area.(5)Development strategies such as Xingmu-Fu and Xinggong-Qing County in the study area have intensified the expansion of grassland and construction land,causing arable land to be eroded by forest land,grassland and residential buildings.There is an urgent need to strengthen the protection of cultivated land and promote the rational use of land.