Extracting and analyzing urban built-up area based on impervious surface and gravity model

Urban built-up area is an important indicator for urbanization as well as the intuitive reflection of a city´s expansion and development. Grasping the range of urban built-up area and the trend of urban extension can guide the conduct of urban planning management and city statistical analysis orderly. Using the eCognition software as platform, the urban built-up area is extracted based on the impervious surface through object-oriented method in this paper, then according to a series of related urban planning standard to make a set of buildup area definition scheme quantitatively through analysis and calculation, so that the belongings of components in the city will be divided effectively. This has broken the idea that dividing the urban built-up area by administrative boundary as before. Then using the gravity model to calculate the gravity between areas, and do the grade division of the extracted urban built-up area. At last, the comprehensive analysis of extension and dynamic and the forecast of a city would be conducted according to the multidate images in order to investigate the center of gravity and the direction of urban development, and provide evidence for urban planning and management. Based on the experiment, this paper came to the conclusion that the range extracted based on the impervious surface can express the urban built-up area range correctly; the range of urban main built-up area calculated by gravity model is also identical with the actual urban center; the urban extension analysis based on multidate images can reflect the urban development and change rapidly and obviously.