Research On Construction Of The Digital Topographic Map And Application In Road Design

Highway transport capacity is facing austere test now in respect that traffic is increasing day by day with the rapid development of our economy, and so the traditional highway survey and design can not adapt to the nowadays highway construction any longer. The matter about how to guarantee the quality and the rate of highway construction is focused currently. A new idea about highway design has been on with the coming of Digital Age, and the way that the highway survey and design is accomplished by making use of digital topographic map has been a new study subject. It will make great sense to highway construction.The paper takes the Xing'an-Yangshuo secondary highway for example in engineering. It states the acquisition about terrain data on the digital topographic map first of all, and discusses the method of getting terrain data by digitization and vectorization on the paper topographic map with R2V software. The data can be regarded as basic data of digital topographic map construction. The method on digital topographic map construction is analyzed and studied in detail, and states the construction method about Delaunay Triangulated Irregular Network (DT). The model is constructed by the Hint digifax software. After that, the interpolation method on digital topographic map is discussed and the theory on linear and quadratic curve surface fitting interpolation is introduced concretely. For the problem about accuracy deficiency of elevation interpolation, the plane interpolation elevation correction method is put forward, and so the DEM plane interpolation elevation correction program is devised on that basis. The program is put into use in reality project, elevation interpolation accuracy is improved evidently. At last, it takes the reality project for example and so discusses the application of the digital topographic map in road design.VB as a design platform, the DEM plane interpolation elevation correction program adds "dihedral angle" to effect factors, which makes the interpolation elevation correction method perfect. The program takes the Xing'an-Yangshuo secondary highway for example, and verifies that the method is feasible and the system has advantages:simplicity of operation, evident correction effect, rapid computational speed, precise result and it has good application. The program has a evident correction effect on the interpolation point inside the triangle but not the one on the edge of the triangle side at all. It explains that the program is appropriate for the correction of longitudinal-section ground elevation but not cross-section ground elevation. The digital topographic map constructed on the base of digitization and vectorization on the paper topographic map is appropriate for the feasibility study and prelminary design stage of the highway project by using digital topographic map in the reality road engineering. The paper reflects that digital topographic map has great application value and will be focus of the study in future work...