Research On Monitoring And Assessment Of Land Ecological Security Based On Data From Domestic Environment 1 Satellite

Taking Zhongxian County as an example,this dissertation is aimed to explore a series of theory and methods on monitoring and assessment of Land Ecological Safety based on data from Domestic Environment 1 Satellite,DEM, administrative area,and Social and economic statistical data.The main research contents and results are as follows:(1)Land Ecological Security Evaluation Model and Index SystemAn AHP model and Index System are built to make an assessment on Zhongxian County Land ecological Security,in which Land Ecological Security Evaluation takes a role as target layer,and the criterion level is comprised of economic factors、natural factors and social factors. As for the factor layer,economic factors include Per capita GDP and Economic density;natural factors are involved with Proportion of Arable land Greater than 25 degrees slope,Proportion of combination with woodland, meadow and territorial waters; natural factors are concerned with Per capita arable land, Natural population growth rate, Urbanization rate, and the Population density.(2) Land Ecological Security Evaluation Database construction①A Pretreatment, including Geometric correction, Mosaic and Crop, was operated in Arc GIS software with data of DEM, domestic Environment 1 Satellite image, administrative area.②Land use information interpreted from domestic Environment 1 Satellite image. Firstly, Interpretation signs were set up accroding to the Land Classification System;Secondly,the land use patches are interpreted from Satellite image,being attached to the attribute data table;Thirdly, land use data is correctedand modified with the result of field investigation;Fourthly,a check procedure is excuted(executed) to judge the actuary of land use data, by compared with the data of the second survey of land use. The results show that Zhongxian wad endowed an area of 2184.68 km2,and Arable land, woodland, meadow and territorial waters, construction land, and Unused land have area of 986.16 km2、861.49 km2、33.28 km2、139.89 km2、159.33 km2、4.53 km2 respectively.③Topographic information extraction form DEM Data. A slope raster data is obtained from Zhongxian County DEM with the Spatial Analysis module in Arc GIS software, during which a cell size of 30m×30m. Then the slope raster data is reclassified to slope degree scope of ≤2°、2°-5°、5°-10°、10°-25°、>25°。④Economic and social data. An attribute data is associated to the administrative division data,in which the data of Total population, Resident population, Township resident population, Births, Deaths, GDP, checked out from Statistical Yearbook, was input and edited to Every Town and Township.(3)Zhongxian County Land Ecological Security EvaluationThe value of every assessment indices is achieved by Land Ecological Security Assessment Database. An overlay analysis is proceeded on the platform of Arc GIS Software. The coverage of slope degree reclassification,land use data of the Year of 2010,and economic and social data are dissolved,calculated,and gathered. The value of every assessment indices are converted to a Standardized value with Extreme value method. Thereafter, a score of Township Land Ecological Security is calculated with the Standardized indices value and weight. Every town and township is classified into kinds of Land Ecological Security Level according to the Grade standards ultimately. The data illustrated that the proportion of Security, Relatively safe, Sensitive, Risk have occupation of 6.207%、35.487%、32.830%、25.476% severally.Land Ecological Security Evaluation Model and Index System, domestic Environment 1 Satellite image interpretation,and Land Ecological Security Evaluation Database construction method,are proved beneficial to preserve Land Ecological Security both in Zhongxian County and Three Gorge Reservoir Area.