The Design Of Active Fault Geographic Information System And Research Of Related Problems

Earthquake is one of the most serious disasters, which causes casualties, economic damage and social turbulence. Though the frequency of destructive earthquake is low, once an earthquake happens, the damage is huge. The earthquake which is induced by active fault with rapid, sudden move is the main cause of city earthquake damage. So it is an efficient way to help related department analyze the location of active fault, study on active fault forbidden region, reduce the loss caused by earthquake, secure lives and properties by establishing active fault information management system. Geographic Information System is a comprehensive subject which involves surveying and mapping, environment, computer technology and other aspects. It is one of the most important means to promote the development of the information society. Whereas the importance of the active fault information and gradual popularity of Geographic Information System, to establish a nationwide active fault Geographic Information System has become an imperative task.This paper takes the "Active Fault Geographic Information System" project as the background, introduces the design and development process of the system. In view of the terrain data used in the system, an effective image compression method is also studied in the paper. This paper is divided into two parts. Part one discusses the principle of Geographic Information System, Components Geographic Information System development, introduces the structure, function design and typical modules of "Active Fault Geographic Information System". Part two of this paper dicusses the methods of the terrain image compression. Generally terrain image which contains great outline and texture information takes up much space in computer disk. In this paper, an embedded zero-block based image compression algorithm is used to solve the problem. It uses set partitioned embedded block(SPECK)coder algorithm, which exploits the hierarchical structure and energy clustering in frequency of an image after wavelet transformation. By this approach, the performance of the embedded wavelet image coder is increased and a low complexity is obtained. The results show that, at a low bit rate, compared with the reconstructed terrain image by SPIHT algorithm, the outline and texture information is obtained better in the reconstructed terrain image by SPECK algorithm. As a result, SPECK is an efficient terrain image compression method.