Influence of Sampling Methods in Combination with Interpolation Methods on DEM Quality

With the programming method,a 30 m×30 m DEM was used to test the effect of the combination of three common used sampling methods(simple random sampling,systematic sampling,stratified sampling) and three interpolation methods including Kriging,Spline,and Inverse Distance Weighted(IDW).Every sampling result of each sampling methods was interpolated using the three ways.Finally,three values were calculated,including the absolute value of the average altitude difference,mean square error and a maximum error of single point.By a combined analysis of experimental results,it was demonstrated that the combination of stratified sampling and Inverse Distance Weighted is suitable for applications that require precise average altitudes;the combination of systematic sampling and Spline is suitable for applications that require precise relative altitudes.