CULTIVATED LAND CHANGE ANALYSIS OF YANGTZE RIVER DELTA REGION BASED ON MODIS

摘要

This Paper uses MODIS data to monitor and evaluate cultivated land changes in Yangtze River Delta region. Firstly, In order to validate the veracity of the classification results by MODIS, Hangzhou city is selected as the experimental area, Spot5 and Landsat scenes in 2001 and 2005 are collected and used to conduct initial validation exercises to assess the quality of land use classification results based on MODIS. The result shows that MODIS could be used to regional cultivated land change analysis. Secondly, MODIS scenes which cover the Yangtze River Delta from 2001 to 2005 obtained from the EROS Data Center (EDC) Distributed Active Archive Center (DAAC), these images are reprojected and resampled, and 6 land use classes are defined and classified: Cultivated land, Grass Land, Water, Forest, Residential Land and Unused Land. After classification, the acreage of cultivated land is counted. Land use digital maps produced by the Institute of Geographical Sciences and Natural Resources Research (IGSNRR) for the study area are also used as the comparative data. And the cultivated land data in 1995, in 2001 and in 2004 are extracted separately. Moreover, in order to analyses the inherent mechanism which brings on the change of the Cultivated land, the paper also use the economic data and population data of the Yangtze River Delta Region. Through discussion, the author draws some conclusions:(a) From 1995 to 2001, along with the economy and urbanization level of the Yangtze River Region developed quickly and continuously, the reduction area of the cultivated land is about 8% of the total area of the land and most of the cultivated land has been mainly changed to the residential and construction land use types, (b) The area which the cultivated land reduction is concentrated around the Taihu Lake region and Hangzhou Bay area, mainly includes places such as Shanghai, Suzhou, Hangzhou, Shaoxing, Wuxi and Huzhou, in addition also has Nanjing, the fact corresponds with the development of economic level of these cities.(c) From 2001 to 2005, the overall change of land tends to steadily, the speed of the cultivated land turn to residential land slows down, however it mainly transforms to forest land, grass land and pound. This indicated that the use type of the land is gradually transformed to the high output per unit in under the economic interest actuation.