Theory And Techniques Of Digital Relief Shading

The perfect realization of the digital relief shading is a task waiting to be done as soon as possible in the development of the digital mapping technology. This thesis discusses on the theories and technologies of the digital relief shading in computer. It puts forward the theoretical framework for the digital relief shading, and conducts an in-depth research on the thorough procedure of the involved technologies, and researches the intelligent of automatic relief shading. Based on the facts mentioned above a software system of digital relief shading is developed and makes a lot of applications. The essential aspects are listed briefly as follows:1. The establishment of the theory of digital relief shading.The thesis expounds the relevant theories of digital relief shading after a summarizing of the theory of traditional manual shaded relief, including a clearly defined notion of the digital relief shading, the underlying theories and system framework. It also provides a detailed analysis of the key technologies for the realization of the digital relief shading. In addition, it probes into the advisable, altered attitude a mapper should adopt while working with the up-to-date technologies. The thesis stresses that a mapper is supposed to make a proper adjustment to the traditional assessment of manual relief shading, understands some characteristic of computer mapping, and be fully aware of the superiority of digital relief shading.2. A systematic study on the supportive data of digital relief shading.The thesis builds the theory of the structure lay about relief representation and discusses the requirements of the digital relief shading mapping for its terrain data. In terms of the mapping of digital relief shading, the thesis argues that the constructing approach of relief models, which is based on the landform structure features, is indispensable to the production of a digital relief shading map of high quality. Moreover, the thesis applies wavelet theory to the generalization and simplification of DEM data, and to the process of the blending of DEM data with varied qualities.3. A systematic analysis on the approaches and procedures of the digital relief shading.The thesis designs a illumination model for the production of a digital shaded relief map, explains the adjustment and use of lights in different mapping places, realizes mathematic controls on the digital shaded relief maps, provides calculational methods for the transformation of images, builds the basic ways of colored shaded relief designs and illustrates some basic measures of color designing to enable the application of several color patterns and their alternations via a computer.4. The thesis argues that the effective approach to produce better shading effect is to make use of arithmetic to simulate some expertise in manual shaded relief. It lists out some ways to perfect and optimize digital shaded relief maps with man-computer interactive software. The thesis also points out that the key to the intelligentizing of relief shading mapping is to transfer expertise into the form that is possible for computer disposal. Based on the facts mentioned above the thesis researches the knowledge express of automatic relief shading , points out the express methods based on rule and model, provides the frame of knowledge representation system.5. By virtue of some case studies of the application of the digital relief shading technologies based of production practice, the thesis gives the detailed introduction and analyse and provides complete approaches to relevant relief shading mapping.