各向异性河床地形空间插值方法比较研究

Comparison of Spatial Interpolation Methods for Anisotropic Riverbed Topography

河床地形是有关河流水环境管理、航道整治、生态保护等研究的重要基础数据,空间插值方法是生成河床地形的主要方法之一。为更好地比选反映各向异性对河床地形空间插值方法的影响,以闽江下游河床地形为研究对象,选取了反距离权重、克里格、样条函数和顾及各向异性的椭圆反距离权重等四种方法,从断面间距和栅格尺度两个方面,分析各向异性对河床地形空间插值的影响。结果表明,当断面间距较小或栅格尺度较大时,椭圆反距离权重方法相对于其他方法模拟精度略有优势;当断面间距较大和栅格尺度较小时,优势较为突出。也即由于椭圆反距离权重方法更好反映了河床地形的各向异性特点,是河床地形空间插值比较适用的方法。

Riverbed topography is an important basic data for the study of river water environment management,waterway regulation and ecological protection.Spatial interpolation is one of the main methods to generate riverbed topography on the basis of sample data.In order to better reflect the anisotropy on the riverbed terrain spatial interpolation method,this paper took the lower reaches of Minjiang River as study area,and selected four typical methods for spatial interpolation simulation,including Inverse Distance Weighting(IDW),Kriging,Spline and Elliptical Inverse Distance Weighting(EIDW,the anisotropic form of IDW).Besides,it analyzed the impacts of anisotropy on riverbed topography spatial interpolation by crossing section spacing and grid scale.The results show that EIDW has slight advantage over other methods in simulation accuracy as the crossing section spacing is small or the grid size is large while its advantage is prominent as the crossing section spacing is larger and the grid size is smaller.EIDW has become more suitable for riverbed terrain spatial interpolation since it well reflected the anisotropy of the riverbed terrain.