A Review of Spatial Interpolation Methods for Environmental Scientists

This review aims to provide some guidelines and suggestions in relation to the application of the methods to environmental data by comparing the features of the commonly applied methods that fall into three categories, namely: non-geostatistical interpolators, geostatistical interpolators and combined methods. Commonly used assessment measures are summarised and the criteria used to judge each measurement are also discussed. Two new measurements are proposed and a procedure is developed to compare the performance of the methods for different variables and from various disciplines. A total of 51 comparative studies on the performance of various methods in environmental sciences are summarised. The performance of 62 methods and sub-methods in the 51 comparative studies is compared. Several factors that affect the performance are discussed, including sampling design, sample spatial distribution, data quality, correlation between primary and secondary variable, and interaction among various factors. The impacts of sample density, variation in the data, sampling design and stratification on the estimations of the methods are quantified using data from 77 cases. A total of 26 methods are then classified based on their features to provide an overview of relationships among these methods. These features are quantified and a cluster analysis is conducted to show similarities among these spatial interpolators. A decision tree for selecting an appropriate method from these 26 methods is developed based on data availability and nature. Finally, a list of software packages for spatial interpolation is provided. Some important factors for spatial interpolation in marine environmental science are discussed, and recommendations are made for applying the methods to marine environmental data.本综述旨在通过对比三类常用空间插值方法的特征，为环境数据应用此类插值方法提供指导与建议，这三类方法分别为：非地统计插值器（non-geostatistical interpolators）、地统计插值器（geostatistical interpolators）以及组合插值方法。本综述梳理了常用的评估指标，并讨论了用于评判各指标的标准；同时提出了两项新的评估指标，且构建了一套可对比不同学科、不同变量下各方法性能的流程。本综述总计梳理了51项针对环境科学领域各类方法性能的对比研究，并对这51项研究中涉及的62种方法及子方法的性能进行了对比分析。本综述还讨论了影响方法性能的多项因素，包括采样设计、样本空间分布、数据质量、主辅变量间的相关性，以及各类因素间的交互作用。本综述借助77个案例的数据，量化了样本密度、数据变异程度、采样设计及分层策略对各方法插值结果的影响。本综述基于方法特征对总计26种插值方法进行了分类，以梳理各类方法间的关联；同时对这些方法的特征进行量化，并通过聚类分析揭示了这些空间插值器间的相似性。本综述基于数据的可获取性与数据特性，构建了一套可从这26种方法中筛选适配方法的决策树。最后，本综述列出了用于空间插值的软件包清单；同时讨论了海洋环境科学领域开展空间插值所需关注的关键因素，并针对如何将此类方法应用于海洋环境数据提出了建议。