Articles | Volume 10, issue 1
Geosci. Model Dev., 10, 239–253, 2017
Geosci. Model Dev., 10, 239–253, 2017

Development and technical paper 16 Jan 2017

Development and technical paper | 16 Jan 2017

A high-fidelity multiresolution digital elevation model for Earth systems

Xinqiao Duan1,2, Lin Li1,3,4, Haihong Zhu1,4, and Shen Ying1,4 Xinqiao Duan et al.
  • 1Geographical Information Science Faculty, SRES School, Wuhan University, Wuhan 430079, China
  • 2Hubei Geomatics Information Centre, Wuhan 430074, China
  • 3Geospatial Information Science Collaborative Innovation Centre of Wuhan University, Wuhan 430079, China
  • 4The Key Laboratory for Geographical Information System, Ministry of Education, Wuhan 430079, China

Abstract. The impact of topography on Earth systems variability is well recognised. As numerical simulations evolved to incorporate broader scales and finer processes, accurately assimilating or transforming the topography to produce more exact land–atmosphere–ocean interactions, has proven to be quite challenging. Numerical schemes of Earth systems often use empirical parameterisation at sub-grid scale with downscaling to express topographic endogenous processes, or rely on insecure point interpolation to induce topographic forcing, which creates bias and input uncertainties. Digital elevation model (DEM) generalisation provides more sophisticated systematic topographic transformation, but existing methods are often difficult to be incorporated because of unwarranted grid quality. Meanwhile, approaches over discrete sets often employ heuristic approximation, which are generally not best performed. Based on DEM generalisation, this article proposes a high-fidelity multiresolution DEM with guaranteed grid quality for Earth systems. The generalised DEM surface is initially approximated as a triangulated irregular network (TIN) via selected feature points and possible input features. The TIN surface is then optimised through an energy-minimised centroidal Voronoi tessellation (CVT). By devising a robust discrete curvature as density function and exact geometry clipping as energy reference, the developed curvature CVT (cCVT) converges, the generalised surface evolves to a further approximation to the original DEM surface, and the points with the dual triangles become spatially equalised with the curvature distribution, exhibiting a quasi-uniform high-quality and adaptive variable resolution. The cCVT model was then evaluated on real lidar-derived DEM datasets and compared to the classical heuristic model. The experimental results show that the cCVT multiresolution model outperforms classical heuristic DEM generalisations in terms of both surface approximation precision and surface morphology retention.

Short summary
This article proposes an optimized transformation for topographic datasets. The resulting topographic grid exhibits good surface approximation and quasi-uniform high-quality. Both features of the processed topography build a concrete base from which improved endogenous or exogenous parameters can be derived, and makes it suitable for Earth and environmental simulations.