The Three-Dimensional Laser Scanning Technology Application In Slop Micro Topogrphy Observation Application

As a new method,terrestrial 3D laser scanning technology can obtain the complete measured target point cloud data quickly and accuratly, so it’s applications in micro-scale erosion monitoring are increasingly used. Microtopography with the surface topography is relatively small after rainfall erosion. If we want to make accurate monitoring analysis to such a small terrain,we need high precision observation instruments, and terrestrial 3D laser scanning technology just meets the requirements of erosion monitoring. High-density point clouds can make a more complete description of one moment of the specific point cloud slope. Compared to the traditional way of observing, the terrestrial 3D laser scanning technology has the characteristics of non-contact measurement, which ensure that the observation of microtopography will not change during the measurement process. The high-precision micro-topography DEM modeled by interpolation of point cloud data can reflect the variety of terrain factor of microtopography accurately and quantitatively.In the course of the study, we use observation data acquired from three kinds of field topography ploughing deeply in 20 cm, ploughing shallowly in 10 cm, bare slope after the four-times-rainfall and observation datas before and after the rain of indoor area including six kinds of terrain ploughing deeply in 20 cm, ploughing shallowly in 10 cm, bare slope, rill with the depth of 5cm, 10 cm, 15 cm under three kinds of rain intensity in 40 mm / h and 90 mm / h, 120 mm / h.Considering the different DEM sampling interval can change the summarize of surface microtopography, leading to the difference between the observation results of microtopography. Gradient, slope direction, slope variability and slope aspect variability in different scale were obtained through the analysis on the point cloud data with Geographic information system software. Changes in topography and roughness of the terrain under field conditions was positively correlated with rain intensity for indoor conditions Roughness very complicated; bare slope roughness change in the case of changes in rainfall intensity farming rather than farming near the rill topography, terrain roughness changes in farming first raze then produce erosion and gully erosion is a direct result of erosion.Sparsing and increasing density are the most two common approaches in the process of dealing with the point cloud data. Concluded for post in undulating terrain smaller curvature calculation using thinning processing speed will increase and not reduce the accuracy; 1mm data extraction roughness variation regularity dilute strong encryption process, you can explore the law, the establishment of thinning the relationship between the scale and roughness, improve computational efficiency by thinning data.Using observation results under field conditions about three kinds of terrain ploughing deeply in 20 cm, ploughing shallowly in 10 cm, bare slope every 15 days, and the data of indoor area including six kinds of terrain ploughing deeply in 20 cm, ploughing shallowly in 10 cm, bare slope, rill with the depth of 5cm, 10 cm, 15 cm under three kinds of rain intensity in 40 mm / h and 90 mm / h, 120 mm / h, roughness of the microtopography were extracted before and after the rain. The results show that changes in topography and roughness of the terrain under field conditions was positively correlated with rain intensity for indoor conditions Roughness very complicated; bare slope in the case of rainfall intensity variation of roughness and not cultivated close Rill farming terrain, rough terrain farming the degree of change for the first raze then produce erosion and gully erosion phenomenon is a direct result of erosion.