Automated Classification Of Micro Landform Based On Grid Digital Elevation Model

Digital Terrain Analysis (DTA) is a topographical information analysis technology to calculate and extract terrain surface parameters and morphological features on Digital Elevation Model(DEM), and the application of DEM is extended by DTA. It is more advantages that topographical information is extracted from grid DEM than from other spatial data. Accordingly, it is very important that the application of DTA based on grid DEM nowadays. Micro landform classification originated from macro landform classification has more extensive application than macro landform classification. And micro landform classification is a means of extracting local special topographical information, it can provide topographical information for many research fields. Whether in macro or in micro, automated classification of landform from DEM is the precondition of DGM data constructed, and is the foundation of landform distributed pattern researched.In this paper, automated classification of micro landform based on DEM and DTA is studied. At first, the definition, development and application of DEM and DTA are explained systematically. The system, gist and method of micro landform classification are summarized. After concluding summary and analysis, it is thought that the key technologies of micro landform classification based on DEM are in two sides, one is how to extract the landform factor efficiently and accurately, the other is how to establish reasonable landform classification decisions. Then the principles and methods of extraction slope and curvature based on grid DEM are studied. Through analysis, it is thought that extraction slope and curvature based on grid DEM lies in calculating derivatives. The unified derivatives formula based on grid DEM are given. Types of slope classification indices are analyzed and described. The slope classification based on geographical research is given, and it is noted that the slope classification based on geographical research has close relation with soil erosion research. In succession, the focus of analysis is on Dragut's research about the hill classification based on slope and curvature. It is considered that Dragut's landform classification indices fragmented the unity expression of the terrain. The slope threshold in soil erosion research is referenced and Dragut's hill classification decision based on slope and curvature is improved as follow-up experiments and research foundation. Finally, the slope classification based on slope gradient and the hill...