The Fine Processing Of Digital Elevation Model And Topographic Factors’ Extraction And Analysis

Digital elevation model is an important part of the basic geographic information data,is one of the core contents of geographic spatial database, which contains a wide range of data information, has high application value,is the data base of the analysis of topographic research. The study shows that using the digital elevation model with different levels of resolution to extract and analyze the information of terrain elements,which is obviously different. In order to get more accurate terrain information,based on1:10000DLG and other related elevation data,refined to generate more accurate DEM data and use the data to extract and analyze the terrain elements in text area.The research work are as follows:(1)A preliminary study on the method of DEM fine processing is conducted and the method is theoretical analyzed.Constructing a series of mathematical surface which is similar to earth’s surface and has different grid spacing,we can obtain the elevation value of each point by calculating, as a theoretical analysis of the data base,construction and refinement of DEM is conducted,the height error and slope error of data processing are analyzed,What’s more,the accuracy of the data evaluation is carried out.(2)Based on the theory of DEM analysis results,we can choose the test area and analyze the elevation data,then obtained the refinement of the data source,In addition,we can design the test process of DEM refinement by checking the data of picture in picture and analyzing the proportion of slope.In the process of refinement,a detailed comparative analysis of the data synthesis method is done by test,select the most effective and reasonable method for the study area,so as to get the results of refine data.(3)Based on the refined data results,the slope to the extraction and classification statistical analysis are carried out.At the same time, to get the undulating topography of the area,the window incremental analysis method is used to calculate the optimal statistical analysis window,the inflection point is determined by means of the mean shift point method on statistic,the best statistical analysis window of the study area is 20*20,area as1600m2,relief map will obtain under the analysis window,most can reflect the features ofthe study area.(4)The accuracy of refine processing on the theoretical model data and actual terrain data is Comprehensive analyzed. We selected three geomorphic features data in Fenyi County,which is used to analyze the precision of the results of refinement,assess the accuracy of the results through the check point,,then get the error distribution of the three terrain data,check the expression of data on the terrain by visualization method.The results show that the DEM fine accomplishments can reflect the terrain of the area clearly and comprehensively,it provides the necessary basic data for the extraction and analysis of topographic factors.