The Optimization And Buffering Strategies On 3D Navigation System Based Urban Pipe-Network

3D navigation subsystem is an important subsystem in the urban pipe-network 3D visualization system. It can give customers better immersion and we can dynamically show the important elements such as spatial relationship and depth information through the 3D navigation subsystem. But it needs acquire data from the database and model the 3D models frequently. It takes a lot of time and has a great impact on the system's efficiency and reducing the user's experience. Therefore, this paper focus on the performance of 3D navigation subsystem, researches and implements a number of the optimization key technologies about 3D navigation subsystem based urban pipe-network, including the optimization of database access technology, buffer strategy and data prediction and replacement strategies,The optimization of database access technology mainly focuses on optimizing the access technology from 3D navigation to database. There are three aspects. The first, we can optimize and improve the spatial data model of urban pipe-network visualization system. The second, we can set up the indexes and procedures about the spatial data model. The third, researching the database connection pooling, we design and implement the database connection pooling for 3D navigation system.Buffer technology is aim to buffer the 3D navigation data which are acquired from database. We buffer data into the memory which is higher speed than database. We also research the multi-level buffering mechanisms and establish it for the 3D navigation subsystem based urban pipe-network.The data prediction and replacement strategies are to predict and replace the data block in the buffer. We study the custom of the users about the 3D navigation subsystem and design the prediction strategies based the statistics. We design replacement strategies in order to store the data block which will be used most likely and replace the data block which will not be used most likely.Finally, this paper describes the design and implement about the new 3D navigation subsystem on the basis of the origin 3D navigation subsystem. The new system applies to the optimization technology mentioned in this paper.