Remote sensing to analysis of the land cover changes in Wuhan from 1991 to 2006

摘要

Rapid urbanization is the main driving force of land cover change in metropolitan Wuhan. This is especially critical with respect to the many lakes and shallow water bodies. Land cover changes from 1991 to 2006 were mapped by classifying Landsat TM images (1991, 2002, and 2006). Different band combinations were used to build high-quality false-color images; the spectral separability of sets of training pixels was then evaluated by contingency matrices and feature space plots. Maximum likelihood supervised classification was applied to extract built-up areas, vegetated areas and water bodies. Post-classification was carried out to detect the land cover changes. From the classification, vegetation and built-up areas expanded at the expense of water bodies. Further comparison of the variety in LULC was analyzed in both temporal and spatial aspects between 1991-2002 and 2002-2006. The growth rate of built-up area from 2002-2006 is 55.7%, which is much higher than the rate from 1991 to 2002, whereas water bodies decreased more in the first period. Vegetation increased in the first period and then decreased slightly in the second. This analysis showed urban expansion is mainly along Yangtze River and along the East-West axis. These spatio-temporal characteristics should allow urban planners to better understand the processes of urban sprawl in Wuhan.