Research On The Construction Algorithm And Application Of Digital Elevation Model

Digital Elevation Model (DEM) plays an important role in Geographic Information System Geographic Database, which is the most important information on the space, the core data system which used to analysis the terrain and one of the important framework data to construct national spatial data infrastructure (NSDI). DEM plays an important part in the related research in terrain analysis and every areas of national economy, for example, Survey and Mapping, resources and environment, disaster prevention, national defense. The key is the modeling algorithm of DEM, especially in the visualization technology of complex data field domain, the speed and quality of modeling have an direct impact on the display performance. So far, some people have put forward several elevation models, the two more representative are Regular Grid and TIN. Regular Grid DEM has many advantages, such as the storage data structure is simple, the remote sensing image data is compound and the surface analysis is good. Based the original sampling data, without interpolation, with a unique, max-min angle, empty circle and so on characteristics, which determine TIN-based terrain model with optimal spatial structure and good operability.This article discusses the principles of DEM and methods of modeling, establish the constraint triangulated irregular network with constraints and establish the Regular Grid. Finally, we focus on the application of DEM in five areas:First, profile analysis, realize the automatic drawing of profiles between any two points.Second, the accurate calculation of earthwork, in the past, the earthwork calculation algorithm of DEM couldn't meet the high-precision requirements. Here, we use the fast processing algorithm which processes the boundary earthwork calculation rapidly, can also improve the accuracy of calculation to some extent.Third, visibility analysis, to determine any two points whether or not is visible.Fourth, contour tracking, draw contour lines based on TIN, using the original observation data directly, not only avoid the accuracy loss of DEM interpolation, but also reach high precision.Fifth, develop an experiment system which use VC + + combined with OpenGL, achieves the three-dimensional display...