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Abstract
A new method for filling voids is developed by improving the approach to high- accuracy surface modelling (HASM), which is based on the first fundamental coefficients and the second fundamental coefficients of surfaces. The first fundamental coefficients are used to calculate the lengths of curves, angles of tangent vectors, areas of regions and geodesics on the surface. The second fundamental coefficients reflect the local warping of the surface, namely its deviation from the tangent plane at the point under consideration, which can be observed from outside the Earth. Nine regions with different landform complexities in hilly, plateau and mountainous areas are selected for testing the performance of HASM by comparing those ones of the classic methods such as triangulated irregular network (TIN), inverse distance weighted interpolation (IDW), advanced Spline method (ANUDEM), Spline and Kriging. The results demonstrated that the HASM void filling always has the highest accuracy regardless of the landform complexity, void area and auxiliary data.
Acknowledgements
This work is supported by Major Directivity Projects of the Chinese Academy of Sciences (kzcx2-yw-429 and kzcx2-yw-308), China National Science Fund for Distinguished Young Scholars (40825003) and by the National Basic Research Priorities Programme (2010CB950904 and 2009CB421105) of the Ministry of Science and Technology of the People's Republic of China. This research was also partially supported by the US National Science Foundation's Biocomplexity and Long-Term Ecological Research (LTER) programmes and the University of California Agricultural Experiment Station. We acknowledge the two anonymous reviewers for their valuable comments and suggestions.