Research And Improvement Of Generating DEM Method By Contour Line

As the multi-scale DEM have established in our country, it is playing a more and more important role in scientific research, production and the construction of national defense. It has become the indispensable source of geographic information system. In recent years, the construction of spatial data infrastructure and the implementation of the strategy of "digital earth", more accelerated the DEM and the integration of geographical information system, remote sensing, etc. Therefore, producing the high quality, high precision DEM is particularly important. Today, DEM has become a common geographic information based products, with the grand scale of production. So how to produce high quality DEM with the best quality and the fastest speed has become a problem to be solved urgently in today’s society.The key to build the DEM is modeling, and modeling is the basis of interpolation. Relatively popular in the market at present, the DEM software such as ArcGIS, VirtuoZo and Demix, they mainly through Triangulated Irregular Network and Grid to make models, although they made interpolation method is more refined according to the different terrain to establish the DEM model is more consistent with real surface. But, in the large-scale production of DEM, now we don’t have any software can be in the absence of too much manual intervention that generate DEM can fully meet production requirement. Starting from the actual application, this paper on the basis of the original DEM generation, by improving the operation method and to join the second development of software, not only makes DEM can meet the national production requirement, but also make DEM production with high automation. The major research contents include:Introduced the basal theory about DEM, including data collection, model establishment and related software, etc. And compared the advantages and disadvantages between each method and software.To 1:10000 DEM production in Yunnan province as an example, This paper introduced its DEM production process and technical index, Then point out the problems in the process of generating DEM (planar static water, plane mountains, plane concave, platform ridge, platform valley, planar flow water), and analysed on the cause of each problem in-depth, and put forward the corresponding improvement method.Due to the particularity of smooth transition to planar flow water, general methods are difficult to solve. This paper researched and development the third party programs for individual treatment. This program based on CAD platform, Using C++ as a programming language. Its main function is to extract each node on the line, and assign height to each node in turn according to the contour. Implement the "line" into "dot", it can make every place of planar flow water has the elevation.Through a lot of experiment contrast before and after improvement, it can be seen from the comparison results in this paper that the improved method is largely improved the precision of DEM generation, not only meet the requirements of the state for the accuracy of DEM production, and also makes the DEM generation efficiency is improved. It has higher practicability.