The Macro-monitoring Of Urban Built-up Area Expansion Based On Domestic Satellite, Hangzhou-bay Area Of Zhejiang Province

In order to meet the demand for the development of social economy, land around urban fringes has been constantly adjusted and configured for expansion of built up areas. Analyzing the spatial variation and expanding tendency may provide important references for urban planning.In this research,3S technology was applied to study 19 built-up areas of cities which were above the county level around Hangzhou-bay area. The macro-monitoring of urban built-up area expansion was launched with the application of 2006 & 2008 remote sensing data from CBERS with multi-stage spatial resolution data. Urban expansion was analyzed based on the information processed by remote sensing technology. According to the information, the driving force of urban expansion was analyzed coupling with economic factors. The detailed results were as follows:1)The total area of urban built-up area in 19 cities above the county level increased from 1320.35 km3 in 2006 to 1458.53 km3 in 2008, which increased 138.18 km3 in two years'period, a rapid expanding trend of cities was presented.2) Among the 19 study areas, Hangzhou city, Huzhou city, and the county of Changxing & Deqing had rapider expanding speed than others, while Shengzhou city and Zhoushan city with no obvious expansion in the period.3)The results of the driving force analysis indicated that there was close correlationship between urban built-up area expansion and many factors, such as population, GDP, the first industrial output, second industrial output, third industrial output, local financial revenue and local financial expenditure, etc. Basically, the correlation coefficient had reached higher than 0.8. However, the relationship between the annual expansion rate of built up areas and the annual growth rate of economic indicators, and the driving function of economic factors for expansion of built up areas were inconsistent among different cities. In these study areas, the county of Huzhou and Deqing had significant expansion rates of 41.99% and 44.69%, respectively, which were significantly higher than the regions' annual GDP growth rates, as well as secondary and tertiary industry growth rates, while other cities showed opposite results. However, after analysis on consumption of built-up area with per unit of GDP growth, we can get that although Huzhou city, Deqing county and Changxing county had rapid expansion in built-up areas, the land use intensity level was lower than Jiaxing and Ningbo city, etc. This may owed to terrains, government guidance and other factors in different cities.4) In this paper, the precision of the results was evaluated in the spatial scales of points and areas based on the validating data obtained from the comprehensive method of RS-GIS-PAD. According to the investigating plan,180 sample points and 54 spots were selected. On this basis, the overall survey areas and individual survey plots were evaluated in the spatial scales of points and areas, respectively. Moreover, the spots with different area levels were evaluated in the spatial scales of areas. The satisfactory results of the evaluation ensured high precision and reliable results.