A Research On The Geomorphologic Characterization Of China Based On The 1:1,000,000 DEM

China new produced 1 : 1,000,000 DEM is a digital elevation matrix with one thousand meters resolution. Its main special characteristic is that it is built by extracting elevations at the kilometer grid intersections of the 1 : 50,000 and 1 : 100,000 topographical maps. However, practicalities and explicabilities of the data in earth science are always a perplexing problem in GIS application. This paper puts stress on the applications of the DEM through extracting basal terrain factors, analyzing area terrain features and classifying fundamental types of geomorphologic form in China automatically. For the DEM possessing high sampling accuracy, the geomorphologic characteristic of whole China could be well represented by four factors obtained from the DEM in macro-space, these are Relief Amplitude, the Earth's Surface Incision, Variance Coefficient in Elevation and Roughness. In addition, it has been proved through a series of statistical analyses that in China the best statistical unit for measuring Relief Amplitude and the Earth's Surface Incision is 42.25 km2. This result provides important basis in further analysis and the classification of fundamental geomorphologic types. In addition, the theories and methodologies of image classification of remote sensing are applied to the classification of geomorphologic types by putting single relief factor in different channels. Experimental results show this improved new method could avoid general technical defects from local neighbor based classifications. This research shows a splendid significance and applied foreground in consummating the theory and methodology of DEM based digital terrain analysis.