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Quality Assessment of Contour Interpolated Digital Elevation Models in a Diverse Topography

Arabinda Sharma, K. N. Tiwari, P.B.S. Bhadoria

Abstract


The present paper address the combined effect of choice of interpolation techniques and grid cell size on DEM quality. Five interpolators namely triangulation with linear interpolation, inverse distance weighing, thin plate spline, ordinary kriging and Topogrid were used to generate DEMs of 30m, 45m, 60m, 75m and 90m resolutions. The relative DEM accuracy were evaluated using elevation accuracy, comparison of derived geomorphic feature, interpolation artifact and spatial variability for three different terrain complexity classes. Results of vertical accuracy showed that there were little variation in RMSE value of different interpolators except Topogrid and effect of cell size was not pronounced in nature. Comparisons of derived basin boundary and stream network with reference one showed a high level of disparity among the interpolators with moderate level of scale dependency. Sink analysis revealed that the different interpolation methods produced DEMs with different level of artifacts. Spatial variability measurement based on semivariogram modeling and entropy indicated a significant difference in spatial information content of interpolated DEMs with changing cell size. Results also showed that Top grid is superior for hydrologic analysis of the basin. But, decreased DEM quality with increasing terrain complexity urge that the accuracy of DEM generated using a particular interpolator and cell size is highly site specific.

Keywords


DEM accuracy, interpolation method, cell size, sink, spatial variability

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