Researches On The Land Use Classification And The Heat Island Effect Of Shaoxing Based On TM Images

With the rapid development of economic and the speedup of urbanization process, it is of great importance to obtain the land use/cover and urban expansion information, analyze its driving force, especially for city construction and environment optimization. Additionally, the intensity of heat island and the problems caused by heat island effect in big cities have been more and more serious and un-neglectful than ever before. It is necessary and useful for city planners and managers to detect the distribution of ground heat field and the factors of heat island rapidly and effectively, which is also significant for solving city environment problems.Based on Landsat TM images and map data, on the Erdas Imagine work platform together with ArcGIS, the TM images were pretreated first, and then the land use classification map of Shaoxing City was obtained after using different algorithms of both supervised and unsupervised classification methods on the study area. With the land use map of Shaoxing in 1992, the area and diversification characteristics of land use in Shaoxing were monitored, and compared with the statistical values, the results proved that remote sensing was precise enough to be used as an important tool of resources survey and town planning. This part focused on monitoring the distribution of water pollution and marine aquaculture shoals requested by project and got a good result.In the next place, the urban boundary of Shaoxing in 2003 and 2006 was extracted through the method of supervised classification, and the conclusion could be drawn that it was viable to extract built-up urban boundary of a city which was crowded by water systems and to compute its area using supervised classification. We carried on the principal components analysis to the correlation statistical data and found that the main driving forces of the urban expansion in Shaoxing were gross national product, living standard, finance and investment, population in turn.In the end, according to the brightness temperature computing mode, planetary brightness temperature (PBT) in urban area of Shaoxing was retrieved by digital numbers derived from the Landsat TM images, which was processed to map the heat island effect. The results indicated that the urban area of Shaoxing appeared to be a heat island distribution, which formed the islands shape in the high temperature region. The high temperature centers centralized in the urban. Widespread water's distribution in the Shaoxing city gained obvious influence to city heat island. It displayed interlacing distribution between the high temperature regions and the low value regions. Water in the city could effectively bring down the surface temperature and relieve the heat island effect, which confirmed the urban water's function of reducing the temperature for the first time in the actual observation. Combining the heat island map with the urban expansion map, the scope of the heat island of Shaoxing expanded with the development of the city while the intension of the heat island did not enhance dramatically.