Application Of Impervious Surface On Urban Build-up Area Extraction And Expansion Analysis

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. While the impervious surface within the city is an important symbol of the urban built-up area. Through the study on impervious surface it can reflect the development and change of the urban build-up area indirectly.This paper studies on the method of impervious surface extraction firstly, and then makes the urban built-up area expansion analysis based on the impervious surface. At last, takes Jiangyin SPOT multispectral image on January16,2003. ALOS multispectral image on November9,2006and ALOS multispectral image on August20,2010as the basis to extract and analyze the urban build-up area, and then to make experimental verification and effectiveness analysis of the theoretical approach.The main job contents of this paper are as follows:(1) Using the eCognition software as platform, the urban built-up area is extracted based on the impervious surface through object-oriented method. During the extraction this paper comes up with a method of IRMAS to select the optimal segmentation scale, in order to improve the extraction precision.(2) Combining with a series of related urban planning standards to make a set of build-up area definition scheme quantitatively through analysis and calculation, so that the belongings of components in the city will be divided. This has changed the idea that dividing the urban built-up area by administrative boundary as before.(3) Using the gravity model to calculate the gravity between areas, and doing the grade division of the extracted urban built-up area. Then making the urban main built-up areas as the important research objects, and the extension analysis of the main built-up areas will be conducted according to the multidate images.Based on the experiment of Jiangyin urban built-up area extraction, this paper comes to the conclusion that the range extracted based on the impervious surface can express the urban built-up area range basically correct after contrast with the city administrative zoning map; using IRMAS method to select the optimal segmentation scales can make the computation process more meticulous and the accuracy of segmentation higher; the build-up area definition based on city planning standard and development situation is more live up to the definition of urban build-up area, and have more flexibility and versatility; the range of urban main built-up area calculated by gravity model is also identical with the actual urban center basically after contrast with the urban statistical yearbook and administrative zoning map; the urban extension analysis based on multidate images can reflect the urban development and change situation rapidly and obviously.