The Application Of Streaming Transmission To The Three-dimensional Terrain Model

3D GIS have been widely used in modern society. As an important part of3D GIS, theterrain is the vector of features in space and the basis positioning other features, and it ischaracterized by a large amount of data. Various fields of the world currently becomeinternet-based from the perspective of information, and people increasingly get or shareinformation from the network. In this case, a growing demand for data network of variousfields is presented. The pressure of network bandwidth is accordingly increased. As a result,there emerges a certain contradiction between the demand for massive three-dimensionalterrain data and limited network bandwidth. Researches home and abroad, therefore, focus onresolving the contradiction.As discussed above, the large amount of data is in fact transmitted in a limited bandwidth.To break this bottleneck, this paper attempts to propose a reasonable data transmissionmethod. The first chapter will put forward this problem and then introduce its research statushome and abroad as well as the main research content of this paper. Based on the basicknowledge of data preprocessing, the following chapter will make a detailed analysis ofterrain data in terms of storage, organization, transmission, cache and experiments. In general,since video streaming transmission can be simply understood as the bottom edge of broadcastwith a lot of time and storage space saved, the reasonable data transmission method on theone hand integrates the idea and technology of video streaming with terrain data; on the otherhand, it uses GPU, the modern hardware resources, to improve such work as thecomputational processing and rendering of the graphics.The analysis of the reasonable data transmission will follow the steps below. The overallapproach starts with blocking the terrain data, and by reference to the idea of multi-resolutionof wavelet transforms, the multi-level model of the terrain data is established, and by adoptingthe coding compression method of wavelet coefficient, the data is transformed intocompressed stream and SPIHT is of good compression effect and also provides conveniencefor streaming data; with regard to the streaming, scheduling pre-fetching data method andtransmission rules are proposed as the viewpoint is used on the side of client; in order tofurther reduce the data throughput and bandwidth pressure, multi-level caching strategy isapplied to. The cache region is set at both ends of system architecture, and the client is alsodivided into graphics cache and memory. In addition, the circular addressing method is usedto update the memory data to effectively use the memory cache space, and the application ofcache approach to the server aims to reduce the number of queries and enhance thetransmission efficiency; the last step is to design and simulate the experimental system andthe results of the experiments is used to verify the feasibility of this reasonable data transmission method. Due to the limited conditions, the data transmission experiments areonly conducted between the client and a high-performance PC using the LAN. The streamingmedia is used to analyze the characteristics of the terrain data, organize data, to reduceredundancy and improve compression. Based on the viewpoint transmission rules, themulti-level cache is used to ensure the last successful real-time data transmission.The last chapter will further analyze limitations of this paper and also point out that moreresearches are needed to deepen this direction.