Based On Dem Terrain Analysis And Visualization

As the digitized relief map, Digital Elevation Model (DEM) has many advantages that traditional relief map does not have, such as the variation of terrain presentations, precision lossless with time going, automation and real-time map plotting. However, the terrain height presented by DEM is discrete, and DEM cannot present the geometry characteristics of real terrain by itself. So, there is a need of theories and methods that can calculate terrain properties, analyze terrain characteristics information based on DEM. This is Digital Terrain Analysis (DTA). The implicit information, such as terrain structure, terrain geometry characteristics can be found by DTA methods, which can be used to quantitatively present the spatial processes, such as digital terrain characteristics in 1-Dimension, 2-Dimension and 3-Dimension, landform structure and river system distributions.Main research points in the paper are as follows:1. Introduced the mathematical theories of Digital Terrain Analysis, described the mathematical models of various terrain surfaces, summarized the terrain with the view of analytic geometry, abstracted and summarized the terrain, analyzed the terrain analytic characteristics, the mathematical definitions of terrain factors, and the related formulations. Shaying River DTA platform was developed based on ArcGIS Engine frame.2. Based on the various mathematical models, the methods to calculate the regular grid based terrain's factors are discussed, and implementations of these calculations are given based on the Shaying River DTA platform.3. Described the common terrain morphologies, introduced the contents of terrain morphology analysis. Especially studied the hydrology application of DTA. Discussed the contents of terrain visibility, terrain view shed and its related factors, and also discussed the basic principle of terrain visibility calculation. An implementation of Shaying River flow network extraction, water shed distilling, and visibility analysis is given based on the Shaying River DTA platform.4. Introduced the related technologies of terrain visualization. The profile analysis, contour, hypsometric tinting, stereo contour, 3D wireframe, 3D surface model, and the animation simulation were implemented on the Shaying River DTA platform.