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An explainable spatial interpolation method considering spatial stratified heterogeneity
Journal article   Peer reviewed

An explainable spatial interpolation method considering spatial stratified heterogeneity

Shifen Cheng, Wenhui Zhang, Peng Luo, Lizeng Wang and Feng Lu
International journal of geographical information science : IJGIS, Vol.39(3), pp.600-626
03/04/2025
DOI: 10.1080/13658816.2024.2426067

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Abstract

Spatial interpolation is essential for handling sparsity and missing spatial data. Current machine learning-based spatial interpolation methods are subject to the statistical constraints of spatial stratified heterogeneity (SSH), normally involving separate modeling of each stratum and simple weighted averaging to integrate intra-stratum and inter-strata features. However, these models overlook the different contributions of inter-strata features to different locations within a stratum (heterogeneous inter-strata associations, HIA) and the explanation of spatial effects on the interpolation process, leading to suboptimal and unreliable interpolation outcomes. This article proposes a novel explainable spatial interpolation method considering SSH (X-SSHM). Spatial and environmental features are utilized to describe intra-stratum and inter-strata information, which are fed into random forest-based learners to achieve high-level semantic feature mapping. Geographically weighted regression is employed to integrate intra-stratum and inter-strata features to achieve a unified expression of SSH and HIA, obtaining the final interpolation result. Geographically weighted Shapley (GSHAP) is proposed to decompose the marginal contributions of intra-stratum and inter-strata features. Model performance is evaluated on simulated and soil organic matter datasets. X-SSHM outperformed five baselines regarding interpolation accuracy. Moreover, statistical methods validated X-SSHM's ability to elucidate the mechanisms by which SSH, spatial autocorrelation and HIA affect the model interpolation process.
explainability spatial association spatial heterogeneity Spatial interpolation

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