Study On Extraction Method Of Vegetation Coverage Information In Yanqing County

Monitoring of a regional vegetation coverage and its change is the important indicators of ecosystem environment changes.There are many methods can be used for measuring vegetation coverage,choosing the appropriate method need according to the practical experimental conditions.Based on the Spot remote sensing data of Yanqing county 2004 and RapidEye remote sensing data of 2011,we use the most commonly used method that is dimidiate pixel model to extract vegetation coverage information of yanqing county in 2004 and 2011,and make some changing analysis.And then using other two model including linear spectral mixture model and the decision tree classification model respectively to extract the vegetation coverage of yanqing county in 2011,and do the accuracy comparison,comparing with the dimidiate pixel model,and then choosing the most suitable method for extracting vegetation coverage information of yanqing county.The last is based on the collected statistical data of social and economic development in yanqing county in 2004-2011,do the driving force analysis,and further formulate some corresponding policies and measures.The main findings are as follows:1)From 2004 to 2004,bare land area decreased,yanqing area of low,moderate vegetation has been reduced.The height of the vegetation cover area of large scale increase.High and high increase of vegetation coverage degree far outweigh the reduction degree of low vegetation coverage.Overall,yanqing county region overall degree of vegetation coverage is constantly increasing.Look from each time:From 2004 to 2011,the highest percentage change is the high coverage,increasing by 12.70%,and the coverage and medium and high coverage area are increasing.Followed by low coverage,medium-low coverage,the change was reduced by 17.59%,7.71%.Yanqing county's average vegetation coverage was increased from 58.99%in 2004 to 80.33%in 2011.A steady improvement in yanqing county in the northeast mountain area coverage and that part of the town fields a wide range of recovery,the overall increased vegetation coverage.2)According to the accuracy of test results,three methods to estimate the precision are over 85%,in this study using the method of linear decomposition of mixed pixels,and the decision tree classification method for the extraction of vegetation information is feasible,the linear spectral mixture model is the highest,90.25%.3)By combining collected economic development statistics of yanqing county,the analysis of yanqing county land use type change driving factors mainly due to population,economic and policy factors.