An Ensemble Framework for Explainable Geospatial Machine Learning Models

The relationships between things can vary significantly across different spatial or geographical contexts, a phenomenon that manifests in various spatial events such as the disparate impacts of pandemics[1], the dynamics of poverty distribution[2], fluctuations in housing prices[3], etc. By optimizing spatial analysis methods, we can enhance the accuracy of predictions, improve the interpretability of models, and make more effective spatial decisions or interventions[4]. Nonetheless, the inherent complexity of spatial data and the potential for nonlinear relationships pose challenges to enhancing interpretability through traditional spatial analysis techniques.[5]. In terms of models for analyzing spatial varying effects such as spatial filtering models[6-8] and spatial Bayes models [9], Geographically Weighted Regression (GWR) and Multiscale Geographically Weighted Regression (MGWR) stand out for their application of local spatial weighting schemes, which are instrumental in capturing spatial features more accurately[10, 11]. These linear regression-based approaches, however, encounter significant hurdles in decoding complex spatial phenomena (Figure 1). Various Geographically Weighted (GW) models have been developed to tackle issues such as multicollinearity [12, 13] and to extend the utility of GW models to classification tasks[14-17]. The evolution of artificial intelligence (AI) methodologies, including Artificial Neural Networks (ANN) [18], Graph Neural Networks (GNN) [19, 20], and Convolution Neural Networks (CNN) [21], has introduced novel ways to mitigate uncertainties around spatial proximity and weighting kernels in GW models. Despite these advancements in marrying geospatial models with AI, challenges remain in addressing nonlinear correlations and deciphering underlying spatial mechanisms.