Abstract: Low-level terraces are relatively easily to extract. We proposed an easier and more useful extraction method. Firstly, the data of the height of terraces are generated with building Thiessen polygon method, and then combining with analysis of their developmental and statistical characteristics of the height of terraces in the distribution area of low-level terrace, this study presented an objective identification in the summary graph of the height of low-level terraces, forming a more systematic and scientific method of extraction and classification of the low-level terraces based on DEM, and provided a new idea for terraces’quantitative research. The study conducted experiment on Wangjiawan gully in the Sanggan River, which showed that the low-level terraces’extraction results based on above-mentioned method is in good agreement with the actual, and therefore the method can be applied to the terraces' indoor interpretation before field survey, and make the field survey work more targeted.

Key words: Low-level Terraces, DEM, Thiessen polygon, Sanggan River