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Southwestern University (2008)

Karst Desertification Investigation Base on ETM Image

Huang Yan

Titre : Karst Desertification Investigation Base on ETM Image

Auteur : Huang Yan

Grade : Master’s Theses 2008

Université : Southwestern University

Résumé
Southwest China is the world’s largest karst area, the strongest developed a rocky desertification land is mainly distributed within this range. Karst rocky desertification and poverty issues of the environment is a global issue, it is a very important factor in the sustainable development of China’s southwestern region of the constraints faced by regional economic. Rocky desertification is a fragile four major ecological environment of western China with one of the (karst, loess, desert, permafrost), it is caused by the deterioration of the ecological environment, land productivity decline, water shortages and poverty in the region. The rocky desertification governance for the protection of national ecological security and the implementation of large-scale development of the western region, reducing regional disparity between the rich and the poor, to safeguard national unity and social harmony is of great significance. Only by fully understanding the current situation of the the Nanchuan city desertification disaster, the analysis of the causes, explore rocky desertification control strategies and patterns, and provide the scientific basis for rocky desertification, can effectively prevent and control desertification, protect the Nanchuan City social and economic health, rapid and sustainable development. This article is in support of remote sensing and geographic information systems, object Nanchuan City expert classification of remote sensing images interprets the software Erdas Imagine9.1 provide image processing methods based on different rocky desertification degree of vegetation coverage, slope, lithology differences to establish a classification rule extraction rocky desertification information relative to unsupervised classification and supervised classification, as well as the traditional visual interpretation of remote sensing image interpretation methods, experts classification faster and achieve a higher accuracy. Determined using the method described in this paper a small area of ??remote sensing image computer information extracted mapping, geometric correction and empirical models of vegetation coverage is key to affect the results of Figure accuracy geometric correction of multi-source spatial information (slope, lithology, vegetation cover degrees, etc.) when superimposed error minimum guarantee ; experience model, in theory, sampling point more, come to experience the more accurate results map accuracy. The survey combined with southwest karst region environmental conditions, research degree and previous work experience, take the following steps : 1. Selected remote sensing image band selection and pretreatment ; normalized difference vegetation index extracted from remote sensing images (NDVI) values, using empirical model, NDVI values ??for vegetation coverage of the work area : 3. establish workspace carbonate distribution database ; 4. establish the workspace slope hierarchical database ; according to the results of previous studies combined with the actual situation of Nanchuan to establish accurate the rocky desertification grading explain. 6. Use ERDAS IMAGINE Expert Classifier, establish the image classification process template extract rocky desertification information is part of the focus of this article. To interpret the results in a GIS platform statistical analysis, and field visits to verify the accuracy of interpretation of the results. According to the status of desertification disaster, analyze the causes, to explore rocky desertification control strategies and patterns. Nanchuan City is the most serious counties of Chongqing rocky desertification through the satellite remote sensing survey Nanchuan City rocky desertification situation in 2000, found out. Interpret the results, rocky desertification and potential rocky area of ??140.43 km 2, accounting for 5.38% of the total land area Nanchuan City, accounting for 11.62% of the total area of ??the carbonate rocks. Potential rocky and mild rocky desertification area of ??109.52km 2, accounting for 77.99% of the rocky desertification area, so in the future in this area should focus on the protection of rocky desertification prevention potential and mild stone desert of the area to prevent further deterioration of its rocky desertification degree

Mots clés : Rocky Desertification Remote sensing Geographic Information Systems Experts Classification

Présentation (Dissertationtopic )

Page publiée le 21 mai 2013, mise à jour le 5 décembre 2017