Detection And Analysis Of Land Use Change In Zhangshui Watershed Based On Landsat Images

With the development of society and the explosion of global population,people’s demand for land resources is increasing day by day.How to grasp the situation of land use change is particularly important today.Using remote sensing technology to detect land use change has always been a research hotspot.Chapter water basin because of its special climate and frequent human activities,lead to the land use cover within the basin has changed significantly,the chapter to explore water basin during1995 to 2020,what changes have taken place in the land use situation,when has changed,the chapter for land use planning of water basin and the dynamic change detection provide powerful basis,Based on the Cloud platform of Google Earth Engine,Landsat images of the study area from 1995 to 2020 were called to make a Landsat remote sensing image dataset with long time series.On the Google Earth Engine platform,Land Trendr time series algorithm and supervised classification algorithm are used to generate the long time series change results of each local class,and the restoration and disturbance change area and the duration of restoration and disturbance change of each local class in each year of Zhangshui Watershed are analyzed from the time perspective.The spatial distribution of species changes in Zhangshui watershed was analyzed from the spatial perspective.The results show that the accuracy of land use classification in each year is higher than 80%,which meets the accuracy requirement of change detection in the next step.Based on NBR,NDVI,NDMI,TCA,TCB,TCG,TCW and other spectral curves,the vertices of sample points in typical regions with changes in Zhangshui Watershed were identified,which verified the feasibility and accuracy of Land Trendr time series algorithm in detecting changes in Zhangshui Watershed.It is concluded that THE NBR index is effective in detecting the change of Zhangshui watershed.Based on the analysis of the changes of the whole Zhangshui Basin,it is found that the changes of the zhangshui basin are most obvious in the northeast and the south,indicating that the areas with significant changes in the Zhangshui basin in recent years are all human activities,such as Nankang district in the northeast and Nan ’an town in the south.The impact of human activities on environmental development is much greater than that of natural evolution of the environment.It was found that the absolute value of NBR difference of the change event from forest to bare land ranged from 0.392 to 0.720.Based on the analysis of the changes of species in zhangshui Basin,it is found that: Chapter water basin water,arable land,forest land,construction land and bare land class disturbance more belong to the sharp changes of disturbance duration more concentrated in 1 ～ 5years,and the change of recovery with the disturbance,class a longer duration of recovery,class recovery time has long have short,both the in situ for a short time to restore the fast recovery of change events,There are also gradual restoration events that go through decades of changes and then return to the original type.