Abstract: Slope is an important factor to describe the landforms quantitatively. In view of the problem of few research on the slope in DEM terrain simplification, the concept and model of slope entropy of points, which can describe the terrain information, are proposed based on the information entropy. And what's more, a new method of terrain simplification is studied. Relied on the data in experimental areas, we compare the new method named SEP with the common method named VIP. It turns out that SEP can retain the terrain skeleton information effectively. In addition, SEP has a better result than VIP in retaining the primary terrain skeleton and abandoning the less important terrain skeleton. The new method has certain reference value for the following study on terrain simplification.

Key words: SEP, DEM, terrain simplification, terrain information, model