Slope And Resolution Studies

Slope is an important factor for soil erosion research, but there are slope attenuation, therefore, can not be directly and effectively the performance of terrain, can not effectively extract the topography and hydrological model parameters associated with the slope, thereby affecting the hydrology and soil erosion simulation accuracy. So how to determine the slope of the variation with the DEM resolution will help to reduce the negative impact from slope attenuation, to improve the efficient use of DEM data resources is important. In this paper, This research was done in the Xiannangou Catchment and the peripheral locality which is a typical catchment within the Loess Hilly and Gully region of Loess Plateau in Ansai Shaanxi. Based large-scale topographic maps,generate multi-resolution interpolated DEM, and extract the slope and profile curvature in the datas, respectively, point, line and surface-level research elevation, slope and profile curvature changes with the resolution reduced, change patterns and their relationship. The main research contents and results are as follows:(1) DEM multi-scale expression and verification of expression effects. Positioning based on the same basis for the establishment of multi-scale DEM, to large scale topographic map data base, generate different interpolation grid size of DEM, and the method of using the histogram similarity generated multi-resolution DEM and topographic maps of different scales match the original DEM to verify the scale effectiveness of the resulting multi-resolution DEM, as the basis of scale effects studies. Through experiments and multi-resolution DEM can be used as the basis of slope-scale effect.(2) The slop scale effect analysis with changes of the resolution.Laid in the high-resolution topographic slope on the feature points, terrain features, combined analysis of regional slope of the overall change in slope with the knowledge to understand changes of resolution, analysis of different resolution. The results show that at the point, line, surface slope region at low levels, little change in slope with lower resolution, and in the high slope, the slope into the attenuation trend with lower resolution, and with the slope rating of higher attenuation of the more obvious trends. Profile curvature of the decay rate faster than the slope of the decay rate.(3) The studies of Statistical analysis of the loss of information with lower resolution and the region of loss information. The results show that the greater the difference with the lower resolution, the more the loss of topographic information, Loss of elevation, slope and curvature of an increasing trend. Elevation and slope information is not lost in the top of the hill, and in the valley part of the larger loss, loss of profile curvature were relatively large in the whole region.(4) On elevation, slope and curvature were to geostatistical analysis. The results show that elevation values are very strong spatial autocorrelation, spatial structure variation and random variation are large, and with less impact on lower resolution; slope and profile curvature, spatial autocorrelation is also great, but the variability and spatial structure random variation is not large, and with the decrease of the resolution, indicating the value of slope values and curvature effects on the regional structure, the ability to weaken.