Study on Spatial Distribution of DEM Interpolation Errors in the Gully of Dry-Hot Valley

To analyze the interpolation errors spatial distribution characteristics of the typical gully of Yuanmou dry-hot valley, the measured elevation points were interpolated by inverse distance weighting (IDW), local polynomial interpolation (LPI), spline with tension (ST), disjunctive Kriging (DK) and triangulated irregular network (TIN)model to generate DEM. Cross validation, relative difference coefficient and the valley lines discrepancy were used to evaluate the interpolation accuracy. The error points with elevation error greater than 1 m were extracted, and their spatial distribution characteristics were analyzed by coefficient of variation(CV), global Moran's index and Getis-Ord G_i^* index. The results show that DK and TIN model had higher interpolation accuracy, the height error points of five interpolation methods were overall aggregating distribution, and the degree was TIN > LPI > DK > ST > IDW. Height errors were significantly positive spatial autocorrelation and TIN model had the highest autocorrelation degree, the hot spots of errors were distributed in the area with large slope.