Terrain visualization of small watershed in Loess Plateau based on contour lines

The terrain three-dimensional visualization of Loess Plateau is a basal research for “Digital Loess Plateau”, which can provide scientific information for research of soil and water conservation. From viewing three-dimensional scene directly in GIS (Geographic Information System) software, it cannot give enough information of interactive communication. To solve that problem, a new means to visualize real sense terrain was supposed in this paper. It combined terrain interpolation algorithm in GIS software with OpenGL programming based on MFC. With the example of Kangjiagou watershed, the contour line data were preceded in AutoCAD and ArcView software to create regular grid DEM (Digital Elevation Model) data of ASCII form. Drawing triangle strip according to those data, calculating the normal value of each point with weighted average model, setting lighting and material model, adding dynamic sky background, making wander scene and view in different directions successfully combined with interactive function, all these ways to make sure the real sense three-dimension visualization of the small watershed had implemented well.