The Simulation Of Flow Path Based On The Terrace DEM

China is one of the most serious soil erosion countries in the world, especially in the loess plateau region. Slope and slope length is the main terrain factors affecting soil erosion. On the scale of watershed and region, the most common method is to use DEM to extract the terrain factors. But most of DEM data simulation is smooth and continuous natural surfaces, now. Even in the new generation of aerial DEM, are less considering it such as widespread riser of terrace, terraced fields in natural or artificial mutation terrain information. Many years of management and construction have built large terrace, greatly changed the surface micromorphology, thus caused the surface slope, flow path and mode change, and affected the soil erosion intensity, especially on the loess plateau soil and water loss region. To seek a method can embed the terraces information effectively in DEM, and explore water way of flow and water flow path in the approximate "levels" of terraced fields. It is the problem to be solved immediately that terrain factors such as slope length extraction, and the soil erosion quantitative evaluation.This research got the following results:(1) Terraces DEM construction method based on real riser of terrace information. It is based on DEM data (1:10000), SPOT remote sensing image (2.5m) and RTK measured data. Extracting two groups of characteristic line, and adding the elevation values for them, within the scope of the remote sensing image terrace, and making use of the two groups of characteristic line as the interpolation property to construct TIN, converting the format from TIN to DEM. And compared to quickly build DEM method, this method can be more real expression of the riser of terrace position, avoid quickly build DEM methods of defects that the riser of terrace height is equal.(2) Terraces DEM (level terraces) hydrological analysis methods of data pretreatment. Equal level terraced field elevation, the field surface can’t flow, causing the need for pretreatment. Connecting the characteristic points of surface water flow by RTK, and importing them into the main channel, makes them form a complete flow. Using the AGREE algorithm repairs the terrace DEM with the complete flow.(3)Fill sinks algorithm of the terrace DEM and flow direction algorithm of the terrace DEM. J&D algorithm and M&G algorithm by C# language fill the sinks; D8 algorithm and MFD-md algorithm by C# language calculate the flow direction and flow accumulation. With comparing different catchment area threshold, it need to extract the channel information under the condition of different filling sinks and flow direction algorithm, validate the terraces DEM flow simulation function module of the actual application effect. At the same time, through the contrast analysis: It is more reasonable that extracting the channel by algorithm of M&G to fill sinks and MFD-md algorithm to determine flow.This study fills the blank of the terrace DEM in flow path simulation, also provides the basis on the process of quantitative soil erosion research.