Guidance: DEM and DTM are mainly used to describe the ground undulations,which can be used to extract various terrain parameters such as slope, aspect, roughness, etc., and perform application analysis such as line-of-sight analysis and watershed structure generation. Therefore, DEM is widely used in various fields.
DEM can be expressed in a variety of ways, including grid, contour, triangle network, etc., this chapter also introduces the conversion algorithm between these expressions, such as generating contour from triangle network, generating triangle network from grid DEM,etc.