The research on the displaying methods of visual digital terrain based on DEM data

A digital elevation model (DEM) is convenient for representing the continuously varying topographic surface of the Earth, and it is a common data source for terrain analysis and other spatial applications. In the mean time, the utility of visual digital terrain is widespread. Thus, methods used for displaying visual digital terrain based on DEM data were to be researched carefully. The paper presents a method of reading the USGS standard format DEM data and gives two ways of displaying the digital terrain´s surface. Triangle mesh is a common and widely used method and has its own merits in displaying, while constructing surface using NURBS curve is another important way. Their difference and similarities was noted. Examples of these two displaying methods were also presented.