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GRID-BASED DEM CONSTRUCTION BY MEANS OF COONS PATCH

A method of grid-based DEM construction in terms of Coons patch has been presented.Two examples including a numerical test and a real-world example were employed to comparatively analyze the simulation errors of Coons patch and the classical interpolation methods including IDW,SPLINE and KRIGING.Gaussian synthetic surfaces with various terrain complexity controlled by coefficient parameters were simulated and the results indicated that with the increase of terrain complexity,the simulation errors of all the methods will increase as well.The Coons patch is much more accurate than the classical methods.The real-world example was used to test the effect of sampling interval on the simulation accuracies of all the interpolators.The results indicate that sampling interval has a negative effect on the simulation accuracy.However,the Coons patch is more accurate than the classical interpolation methods regardless of sampling interval.In terms of simulation accuracy and computing speed,Coons patch can be considered as an alternative method for DEM construction.