Digital Terrain Models

摘要: ADigital TerrainModel (DTM) approximates a part or the whole of continuous terrain surface by set discrete points with unique height values over 2D points. Heights are in approximation vertical distances between and some reference (e.g., mean sea level, geoid ellipsoid) geodetic datum. Mostly arranged terms regular grids, typically given as coordinates (latitude longitude), planar (North East values). DTMs usually assign single value to each point, so cannot describe features cliffs). therefore “2.5D” rather than truly 3D models (Weibel Heller, 1991). While represent bare ground terrain, Digital Surface Model (DSM) describes heights vegetation trees) man-made buildings) too (Fig. 1). It is thus important distinguish DTM DSM vegetated built areas. A closely related term Elevation (DEM), which sometimes used synonymously DTM, but often an umbrella both (Wood, 2008; Hutchinson Gallant, 2005; Shingare Kale, 2013). DEM for elevation from remote sensing radar photogrammetry). These unless building removed. The concept not only limited Earth’s visible surface. also finds application bathymetry (digital describing geometry floor), polar geodesy bedrock rock below ice sheets), planetary sciences surfaces), among many other areas application.