Landsat TM images were employed to characterize land-cover types and land-cover changes in Fuqing City and its adjacent areas in Fujian Province, southeast China. Three TM scenes from 1991, 1994 and 1996 were used to cover the city and the adjacent areas and a ®ve-year time period. Socio-economic data were also integrated with remotely sensed data for the study. Digital image processing with assistance of GIS has produced three classi®ed image maps. The comparison of the three maps reveals that the urban expansion was very rapid, a large number of arable lands have been lost, and deforestation has taken place in the study area during the ®ve study years. The main driving forces to the urbanization appeared to be the rapid economic development and trac infrastructure. The suggestion on the regional sustainable development for the county is also presented.

The normalized difference water index (NDWI) of McFeeters (1996) was modified by substitution of a middle infrared band such as Landsat TM band 5 for the near infrared band used in the NDWI. The modified NDWI (MNDWI) can enhance open water features while efficiently suppressing and even removing built-up land noise as well as vegetation and soil noise. The enhanced water information using the NDWI is often mixed with built-up land noise and the area of extracted water is thus overestimated. Accordingly, the MNDWI is more suitable for enhancing and extracting water information for a water region with a background dominated by built-up land areas because of its advantage in reducing and even removing built-up land noise over the NDWI.

阐述了基于影像的Landsat TM/ ETM+ 的数据正规化技术及其发展。该技术通过将Landsat 影像的亮度值转换成传感器处的辐射值和反射率来对影像进行辐射校正。实例表明,使用正规化技术处理后的影像 可以明显削弱日照和大气的影响, 去除它们产生的噪声;其所求的传感器处的反射率与地面实测反射率的 RMS 值非常小