A Research On The Uncertainty Analysis Of The Digital Elevation Models Terrain Representation

The issue of Digital Elevation Model data uncertainty is the hot focus for the Geo Info System uncertainty research in the world in recent periods. A brief reviews are made on the worldwide study of DEM accuracy, and then the technology and method of uncertainty analysis is presented for further research. The objective of the research must be clear as it defines and documents the conception of DEM terrain representation error and its uncertainty problems being studied in the work. This paper has attempted to illustrate the techniques in capturing and producing DEM, extracting the uncertainty analysis values of DEM in terms of how bias and errors are produced, and visualizing the digital information of DEM data and its errors. Error Map overlaid on the contours and spatial autocorrelation index proved to be an effective method expressing and describing the spatial structure and spatial distribution of DEM errors.Analyzing the grid DEM data concluded the different spatial resolutions and the variant map scales from the Loess Plateau and the Yangtse river of China, especially the DEM spatial datasets with five-meter fine resolution, the uncertainty analysis experiments of the terrain representation errors are put forward with the knowledge of the terrain variability and the spatial resolution of the DEM under something with elevation sampling accuracy. The influences of DEM uncertainty on topographic feature variables, such as slope, aspect, horizontal curvature, and vertical curvature, with statistic mathematics formulation, are also discussed.The research shows the light on the construction of the national spatial information datasets and the composition of the geospatial data mapping standards, and will be as a rule in appraising the accuracy and fidelity of the geo-reference terrain analysis.