Land Use Monitoring And Ecological Service Value Evaluation Of Zhongning County Based On Coupled Object-oriented And Pixels Classification

This paper takes Zhongning County as the research area,and uses Landsat 8 OLI image to explore a fast and accurate land use information extraction method for the regional climate and topographic features of the Loess Plateau.Based on this method,the land use information of the study area is extracted,the trend and driving force of land use change in the study area are analyzed,and the change of ecological service value in the study area is analyzed.The specific research methods and conclusions of this paper are as follows:(1)The Landsat OLI image and the GDEMV2 30 M resolution digital elevation data(DEM)are used as data sources,and the coupling is based on pixel and object-oriented classification.Combining the decision tree classification method with the random forest classification method(Random Forest),the method of extracting land use information suitable for arid and complex terrain is proposed.The method was applied to the land use classification of Zhongning County,and the land use data from 1990 to 2015 was obtained.The results show that compared with pixel-based classification and object-based classification,the overall classification accuracy of the method is greatly improved,and the combination method can obtain higher classification accuracy.The overall classification accuracy of the study area was 74%,and the Kappa coefficient was 0.69.(2)Taking land use change as the entry point,using land use transfer matrix analysis,leading degree analysis,and superposition analysis to study the land use change in Zhongning County from 1990 to 2015.The results show that the overall utilization of land in the study area is increasing,and the land use changes drastically;the overall land change trend is the reduction of unused land and low coverage grassland area,and the increase of cultivated land,sand control land,medium coverage grassland,construction land and forest land.The main types of land use conversion are unconverted land converted into low-coverage grassland and cultivated land,and low-coverage grassland is converted into cultivated land,sand-pressed land,and medium-coverage grassland;economic factors and ecological policies are the reasons for the increasing use of land in the study area and the dramatic changes in land cover.(3)Based on the land use change data of Zhongning County,based on the reasonable correction of the equivalent value factor of ecological service value,the ecological service value and its changing trend and leading factors in Zhongning County were analyzed.The results show that the total value of ecological services in Zhongning County has improved in the past 30 years,and the ecological environment has improved significantly.This change is mainly affected by the positive changes in forest land and cultivated land area.