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.
Citation
ID:
163750
Ref Key:
duan2017geoscientifica