Study On KH-4B Image Processing And Rocky Desertification

Rocky Desertification,a serious natural disasters in Karst area of southwest China,restricted the development of local social economy and was noticed by the country.In order to use scientific methods to adequately manage rocky desertification and solve poverty alleviation tasks in rocky desertification areas,it is necessary to fully understand the process of formation and evolution of rocky desertification.The evolution rules and the causes of rocky desertification are also requisite,certainly.For this reason,this paper selected the Wenshan area,in which the most severe rocky desertification in Yunnan Province.The KH-4B satellite images of Mission 1105-2 and Mission 1106-2 in the 1960 s were downloaded from the USGS website.There are 120 scenes in 30 scenes(each scene is cut into 4 small ones).The research results based on this data are as follows:1.Through analyzing the panoramic deformation of the image,the 30 images were geometrically corrected,radiation treatment and completely seamlessly splicing using the polynomial model inserted in the elevation correction term in the image preprocessing stage,and then the first high resolution full-color image of Wenshan Prefecture was obtained through cropping in the sixties.It is a kind of historical research data for researchers in wenshan area.2.Downloading the 1987 TM image and DEM image data.The slope map,the TM image of Wenshan Prefecture in 1987,and the slope map of the vegetation coverage map were obtained.The classification method of decision trees was used to classify TM image,and then the distributionbof rock desertification in Wenshan Prefecture was obtained in 1987.3.A multivariate data set was built up by using the ancillary data,such as 1987 rocky desertification data,TM image,vegetation coverage map,and gradient map.Then combining the KH-4B imagery and literature data to determine visual interpreting signs,and interpreting images by human-computer interaction using ARCGIS software,obtaining the rocky desertification distribution in the 1960 s.4.By comparing the data of rocky desertification in the 1960 s,1987,2005,and 2017,we obtained the evolution rate of rocky desertification in Wenshan Prefecture in the past 50 years.Combined with the population change data,vegetation cover data,economic development data and other data in Wenshan Prefecture,this paper comprehensively analyzed the major factors of rocky desertification in Wenshan,which include the evolution of natural factors and human factors.The human factors are the main factors,incorporating the change of the social background at that time,the increase of population,industrial development imbalances and the drive of national policy.Based on remote sensing image,this paper constructs the multiple data sets combined with the DEM data,the vegetation coverage diagram,population data and economic development data in the study area,using nearly 50 years' rocky desertification evolution rate in wenshan,comprehensively analyzed the evolution law and the causes of rocky desertification began the 1960 s.It provides a basic idea of scientific method to solve the problem of rocky desertification for future study.