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The use of remote sensing images of the area of ??land use / land cover change monitoring global change research in key areas and basic methods. Hengshan County is located in northern Shaanxi Ecotone hierarchical taxonomy TM images of land use / land cover information extraction and classification recognition, thematic maps of the two periods in 1986 and 2003, analysis of land use / land cover changes of the main results are as follows: (1) based on the spectral characteristics of surface features on the TM images, choose a different characteristic parameters of layers and extract the relevant information: First with TM5/TM3 extract water, and then separated by NDVI vegetation and non-vegetation; combination in non-vegetation zone, with NDBI and NDVI Extract Urban Land separated from the sand and weeds, and then TM5; vegetation zones, NDVI divided into three The class: grass, dry and shrubs, irrigated land and woodland, the last distinction between dry and shrubbery, with TM4 TM5-TM4 difference irrigated land and woodland separation. The accuracy of the results of the evaluation show that the overall classification accuracy of 86.8%, and Kappa coefficient of 0.8506, reached classification requirements of the standard. (2) Hengshan County in 1986, the main land use patterns for dry land and grassland, accounting for 36.62% and 18.87% of the county area; 2003 land use patterns of the bushes and grassland, accounting for 32.91 percent of the county area and 22.46%. (3) 1986 to 2003, Hengshan County land use / land cover change in the overall situation: irrigated land, woodland, shrub, grass and weeds land area increased, the largest increase in shrub land; dry land, waters and sand The land area is reduced, the greatest decline drylands. 1.71% annual rate of change of land use, urban land, shrubbery, irrigated land and forest is an annual increase rate of 14.12%, 6.99%, 4.14% and 1.80%, respectively, while the sandy, dry land and waters annually a decrease of 3.85%, 2.56% and 2.49%, respectively. (4) 1986 to 2003 the Hengshan County land use conversion type: the drylands into woodland and grassland, the the the conversion area were 51237.09hm2 and 32802.57hm2; grass transformed into shrubbery, conversion area 34209.13hm2; waters into water The irrigate conversion area 1524.57hm2; Saudi shrub and grassland conversion the the conversion area were 6548.64hm2 and 15455.34hm2. Conversion of unused land within the strong, mainly sandy grassland conversion conversion area 16747.31hm2.
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