Research On Automated Relief Form Types Classification Of China Based On DEM

The evolution of relief form has long-term characteristic inthe time and broadness in spatial scale. A geomorphologist usually can't see entire process of the evolution of relief form by himself. With the modern science and technology progress, the modern geomorphology transforms from qualitative description to quantitative research The paper researches on relief form of China based on the 1:1,000,000 DEM of China with one thousand meters resolution, with powerful technical support of GIS technology and other disciplines, quotes remote sensing image classification principle, puts forward a new method of automatic classification of relief form types, classifies relief form of China into plain, hill, low mountain, low mid-mountain, high mid-mountain, high mountain and highest mountain. The study extracts and analyseses terrain information based on DEM, determines the optimal combination of classification indexes. In addition, a "multi-spectrum" image is compoed by the optimal combination of classification indexes. And unsupervised classification method is applied to the classification of form types. Accuracy assement is done make reference to Geomorphological Map of China and Its Adjacent Area (1: 4,000,000 scale). Experimental results show that the optimal combination of classification indexes includes elevation, total accumulation curvature, slope of slope, hillshade, variance coefficient in elevation, contour linedensity, and range. The importance arrangement of classification indexes is: elevation > variance coefficient in elevation > contour linedensity > range > total accumulation curvature > slope of slope > hillshade. This method takes into account various terrain characters, may choose no classification scheme, has high automatization degree and small work, the classification result is satisfied. The method can avoid defects of general classification techniques.The research has important meaning and application foreground for terrain information mining of DEM, practicalities of DEM in geomorphology, quantitative research of geomorphology, popularization of relief knowledge, production and use of relief, and so on.