顾及空间异质性的断裂地形区高精度DEM建模方法

A High Accuracy DEM Interpolation Method Considering the Heterogeneous Distribution of Elevations in Areas with Breaklines

  • 摘要: 在数字高程模型(Digital Elevation Model, DEM)建模过程中, 传统插值方法以地表光滑连续为基本假设且只考虑了采样点和待插值点之间的空间相关性,忽略了诸如断裂线等不连续地形特征带来的空间异质性影响,导致断裂线周围的高程被平滑,进而使得构建的DEM 失真。 针对上述问题,本文提出了一种顾及空间异质性的多元径向基函数插值方法。该方法耦合了空间距离、高差、法向量三种地形信息, 充分考虑了采样点和待插值点之间的空间相关性和地形特征异质性,确保地形断裂区 DEM 高精度建模。采用 ISPRS 提供的 10组公共数据以及 1 组机载 LiDAR 点云数据为研究对象,将本文方法与结构张量约束的插值方法以及 3 种传统插值方法(包括标准径向基插值法(Radial Basis Function, RBF), 不规则三角网法(Triangulated Irregular Network, TIN), ANUDEM 法(Australian National UniversityDigital Elevation Model))比较表明, 本文方法的平均总误差最小, 插值性能最优, 而且还能较好的保持断裂地形特征。

     

    Abstract: Objectives: In the process of digital elevation model (DEM) modeling, the traditional interpolation methods are based on the assumption that the surface is smooth and continuous, only considering the spatial correlation between the sampling point and the interpolated point, while ignoring the influence of heterogeneous distribution of elevations in areas with breaklines. This causes the elevation around the breaklines to be smoothed, and distorts the constructed DEMs. Methods: Therefore, this study proposes a multivariate radial basis function interpolation methodthat takes into account spatial heterogeneity. This method couples three kinds of terrain information, including spatial distance, height difference, and normal vector, and fully considers the spatial correlation and heterogeneity between the sampling point and the interpolated point. Results: Taking 10 public datas provided by ISPRS and 1 airborne LiDAR point cloud data as examples, we compared the proposed method with the interpolation method that considers the structural tensor constraint, and three traditional interpolation methods including standard Radial Basis Function (RBF), Triangulated Irregular Network (TIN), Australian National University Digital Elevation Model(ANUDEM). Results show that the average total error of the method in this paper is the smallest, the interpolation performance is the best, and it can better maintain terrain features in the breakline area. Conclusions: In short, the quality of the treatment of breakline terrain largely affect the authenticity and accuracy of the DEM's terrain expression. The proposed method can effectively capture the spatial distribution characteristics of breakline terrain, which is conducive to achieving high-quality DEM modeling.

     

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